A/N: I have no idea where the hell this came from but voila. Take place 1985ish in the universe from the end of Part 1.
It starts with an argument because he came home drunk again, and it's one of their best- Amy's articulate and Biff's vicious and the shouting gets louder and louder. The kid's asleep upstairs and Amy would be worried that their fighting might wake him if she weren't so focused on throwing insults in her husband's face like she's striking matches, match after match from those stupid little boxes he'd had printed up.
And the screaming goes on and on like it always does, but this time is just a little different because this time she's only screaming to drown out the terrified rushing in her ears, and because this time Biff didn't start it, and because at some point Amy's voice breaks and she just starts crying. "Biff," she says, "Biff, I- I went to the doctor again today."
And then it all comes out, the painful truth they've both been avoiding and the screaming stops and he's just holding her next to the kitchen table and she cries and he tries to comfort her, as if he's the kind of person who could do that. They drain the liquor cabinet and talk all night without really saying anything.
After that it's like a switch has been flipped. They never fight anymore, and when they speak it's always in a whisper, like they're going to bring on devastation sooner if they talk too loud. Almost everything they tell Biff Jr. is a lie, because no way could he handle what's really going on.
Biff stops coming home drunk, he just comes home and stays up drinking in the living room, running every now and then to hold back Amy's hair when she's sick, when she retches like she's never going to stop and he wraps a hand around her shoulder and thinks Maybe this is it, maybe this is the last time I ever hold her.
It's like for ten months he's nothing but a husband. His job suffers and he does nothing for himself, and anyone who'd known him before the diagnosis might have thought him a completely different person. It isn't so much that he's changed, though, just that everything else is slowly draining out of him- the movies he liked to watch, the places he liked to go, who he was- leaches away as Amy grows worse and worse.
One night she's feeling surprisingly better, and she wants to go out. Of course she can't. Of course she's not that better, but he wants her to be happy (and imagine that, him wanting happiness for someone other than himself), so he puts on some old Platters record and moves the kitchen table out of the way to give them floor space and he twirls her across the room like they're teenagers again. Except it isn't how either of them danced when they were that age, and there's nothing showy or exciting. It's more like they've both aged thirty years and can't move much but are determined to.
It's while he's holding her waist and swaying without really moving his feet while "Only You" plays that he leans his face into her unkempt hair and honest-to-God cries for the first time since he was a kid. He keeps telling her I can't do this, I can't do this, and even though he feels selfish he keeps going, Can't do this without you.
And she's scared too, she's just as scared, but she wraps her arm more tightly around his shoulder with what little strength she has and says, "Yes you can. You've just never had to before."
Amy dies a week later, and Biff isn't even with her when it happens, he's downstairs teaching BJ how to tie his shoes, and while in the next few weeks he'll blame the kid and he'll blame the damn shoe company, eventually it comes back to hating himself.
The funeral's nice enough, except of course it's a funeral, and also her family's there. At the wake Biff tenses up when he sees her mother like she's going to hit him, but all she does is pat his arm and make some comment about, "She loved you, Amy did, and you were so good for her."
And that's it, that's when he can't take it anymore, he can't stand in there with all these black-clad weepy people and the flowers Amy wouldn't have even liked. "Don't talk like that," he mutters, and he should have stopped talking then but he just gets louder. "You hated me, you still do, so don't act like we're all friends now because Amy's dead." She looks startled and he just keeps going, "I wasn't good for her. Nothing about her life was good. You know something? She deserved a hell of a lot better than what she got, and what she got was me. And that's… that's bullshit. Alright?" And he grabs BJ away from Amy's grandmother and pulls him out of the cramped funeral home and never looks back.
It's a year later when he finds himself standing in a graveyard, again holding his son's hand, rereading the inscription on Amy's headstone that just seems way too simple for her. He feels like he can't even move with BJ there so he leans down and tells him to go find some flowers for Mommy, because yeah, maybe he thinks the flowers are stupid but it seems important for the kid.
"Hey, Ames," he says in a low voice when BJ's gotten far enough down the row. "Can't believe I'm doin' this, because I know you can't hear me. I know you can't, and I… I need you to. 'Cause I need you to know… I'm sorry. I'm sorry I wasn't good enough for you, and I'm sorry you only got one husband and it had to be me, and… and I'm sorry this is the first time in my life I've ever apologized for anything." He stays there apologizing for a long time, until he's somehow stretched out on the ground and BJ wanders back over to him and crawls into his lap and he doesn't notice he's crying until he sees that his son is too.
And all he knows is that he never wants his son to ever have to feel this way, and so next to that inadequate gravestone he swore he'd raise a man who could be better.