If he's going to be the irresponsible father, she must perforce play responsible mother. Otherwise it would all fracture, the smoothly working machine, the esprit de corps, the fucking family dynamic that they've built for themselves. Nate gets to be the proud papa, pushing his young'uns to do better, better, make daddy proud. It works, and they are what they are, but sometimes she's so tired of her role, tired of being the quiet underpinning voice of reason when Nate has had one too many brilliant ideas, or when he's found another great plan at the bottom of his glass of scotch. Is that unfair of her? Perhaps it is. Most days, she loves who they are, how they work as a team, how Nate leads them into battle and brings them home again. But there are also days when she wonders how much more of this she can take.
Eliot knows his role as well as she does. Reluctant uncle, big brother, the one who brings them back safely in the teeth of the enemy, time and time again, even if they don't know what it costs him to do so. Eliot gives his loyalties where he chooses, and he's chosen them, and so he bears each new bruise without flinching.
Nights after the hard jobs, the squeakers, the ones where they shouldn't have made it out, he shows up at her front door. Sometimes they make it to her bedroom, where he lies back into thick eiderdown while she rides him, her hands against his chest, her thighs around his hips. Sometimes they don't make it that far, and end up perched on the kitchen counter in their haste, her skirt rucked up, his jeans sliding down.
Every family has their own ways of coping.