Donnie knew he was different from his brothers ever since he was little. Well, to be fair, all his brothers were different, but he meant different different. Like how they all would be talking about whatever, and when he'd join the conversation in his own Donnie way- maybe a little too sarcastically or just stating the facts- he'd get a head turn or an awkward smile. He wished he knew what his brothers were thinking when they made those faces and gestures after he said something that was apparently a little too weird for them. Did they think he was annoying? Stupid? Crazy?
And then there were the times when he'd find something cool, parts he could salvage and make something great out of while they were dumpster diving. He was always so excited about a great find like this, often ranting and raving to whoever was closest about what he was going to make and how. It was fun for him, working out his plans verbally and getting a visual on his new ideas while expressing his passion and interests to his brothers. Sometimes he didn't always pay attention to their body language, but he got the sense that they weren't always listening. Or that maybe they were listening, but they didn't really care or understand much.
"That's boring." Leo had huffed at him one day when they were 8 after Donnie had burst home to declare his latest innovation.
"It's not boring." Donnie fired back, offended. "Just because you're not smart enough to understand how awesome it is doesn't make it boring. This is going to change our lives!"
"Hey! I'm plenty smart! I just don't wanna hear you go on and on about a new invention again!" Leo replied, fiddling with an old skateboard he had found last week.
Donnie didn't know why that remark had hurt him in just the right way, but it did. "Well, fine then. I'll just go find somebody smarter to talk to." He stormed off to go find the one brother who would always listen, Mikey.
Mikey didn't mind listening to Donnie rant about an invention one bit. He was cool like that. Often times, he'd be drawing or painting something while Donnie rambled, and he'd even go so far as to ask a question here and there. In return, Donnie always listened whenever Mikey found a new show, activity or drawing that he was just really into. The two were symbiotic like that, in a way.
The worst part, though, about Donnie being different were his feelings. Sometimes he felt like he wasn't feeling enough, or he wasn't feeling in the right way when his brothers would get sad or mad or happy about something that he just wasn't as excited about. Most times he'd just go along with how his brothers were feeling about a particular issue, but it got difficult when they were torn. When that would happen he would just stick to the facts and logistics about whatever was happening, and his brothers would always get mad or confused at him for it. Then he just felt like an alien, or a robot, and that made him feel downright awful.
Other times, he found that he was feeling too much. Maybe he was trying to get in the zone and work in peace on a latest project and his brothers kept bugging him, or maybe he had a bad day out scavenging for more parts, or his project just kept falling apart. Whatever it was, it always felt like it would build and build like a wave until it all came crashing down on him and he would just snap. Suddenly everything felt too much, too loud and bright and felt too close. He'd rip off his goggles and cast them aside, only to grip his head so hard that it hurt. He'd stomp his foot and shake his hands, screaming and sobbing in pain. If it was getting particularly bad he'd start banging his head against the floor or wall, at which point one of his brothers would go get Splinter to intervene.
It was never fun when Splinter had to get involved, because he was already hurting so bad and didn't anyone to touch him, and he loved his dad and knew he just didn't want Donnie getting hurt, but it made him feel like a baby. Nowadays he'll just find a pillow for Donnie to slam his head against, but it was the worst when Splinter was still a new dad and didn't quite know what was going on with his son. He just saw that his son was in pain and trying to hurt himself, and thought it'd be best to to just restrain him until he calmed down. It was hell for Donnie, though, to be held down by his dad when all he wanted was to break away and make it all stop hurting.
Then there was afterwards, when he was calm but not calm enough for any exciting activity. He'd mope in his lab draped by his blanket with a cup of hot cocoa, watching some Jupiter Jim re-runs and temporarily turning his brain off. He always hated the way his brothers looked at him when he got like that. Confusion, fear, and concern. His meltdowns always preluded by an 'uh-oh' and 'Don's havin one of his freak-outs!' His brothers always stared at him afterwards, unsure of what to do. Sometimes they tried to offer their comfort. Sometimes Donnie would accept, and other times he just didn't feel like dealing with them right away. It made him feel like a freak, an outcast.
Why him? Why'd he have to be the one who didn't get feelings, who was too smart for his own good, who's entire world could come crashing down around him at any second?
He, at least, found a word for it when he was 9. When he was out scavenging for parts, he found a book. It was titled 'Psychology 101', and it seemed interesting enough, so he took it home. It was a quick read too, as most things were for Donnie. What really interested him was the passage about autism. His eyes barely left the page as he steadily realized that nearly everything in there was him to a T. After figuring out what it was, that he wasn't crazy, he did further research online. Pouring over countless articles and 'Am I Autistic?' quizzes, grinning to himself as he found even more words to describe what he was going through. That him wanting to make things and design tech was called a 'special interest', that when he was having a meltdown it was called 'sensory overload'. That when he flapped his hands or tapped his feet it was called 'stimming'.
After a day of research, he grabbed the book and his laptop and padded over to the living room where Splinter was most likely watching TV. "Dad?" He asked, tugging on his father's robe.
"Yes, purple?" Splinter replied, not turning his attention away from the TV.
"I found this book today, and I've been doing a lot of research on it, and... I think I'm autistic. It's why I have trouble with certain social situations, and I'm so into my tech, and why I have meltdowns. That kind of thing." Donnie said, rocking on his heels nervously.
Splinter turned his attention fully to his son at this point, choosing his words carefully as he spoke. "Yes, I know what autistic means. I have... had my own suspicions for a while now. I just didn't know if I should be the one to bring it up, with my lack of expertise." He paused for a moment, before reaching down to take Donnie's hand in his own. "Donatello, if this is how you feel comfortable defining your experiences with the world, then far be it from me to tell you no. You are my son, and you are so smart and I love you very much. Just know that I will try my best to understand and accommodate you as need be, and the same goes for your brothers."
"Uhh... Wow." Donnie blushed, not quite knowing what to do with the praise and his father's wise words. "Thanks, dad..."
"Anytime." His father replied with a smile, before turning back to the TV. "Okay, show's on."
Donnie spun on his heels and bound out of the room with a smile on his face. He was practically buzzing with excitement, he was ecstatic! He certainly didn't know what he expected, but it still went really well! He was autistic, he knew who he was and what the words were for it, and knew that there were billions of other people walking around up top just like him. Now all he had to do was tell his brothers.