okay but imagine that james wasn’t in the house that halloween. he was talking to dumbledore or out to get groceries or anything that has him out of the house. so lily is home alone but she still sacrifices herself for her son, so the curse still rebounds and hits voldemort and “kills” him. so harry is still the boy who lived, but james is alive.
and of course it’s awful. it’s a terrible moment, burying lily. james is devestated and has no idea how he’s going to raise harry alone. he has to testify that peter betrayed the order, because he’s alive to pass on the knowledge that peter was his secret keeper, not sirius. sirius doesn’t go to prison because he’s too busy helping james cope with lily’s death to go after peter, and peter’s already faked his death by the time he can leave james.
remus and sirius move in with james to help take care of harry, because he swears he can’t do it on his own. remus doesn’t have to focus on rent and food money because james tells him he’s family, so he can focus on a job he actually enjoys such as editing or writing, something freelance so he can take full moons off and no one will wonder why.
sirius refuses to get any job beside full time babysitter, curls up as padfoot and keeps harry warm and safe, especially when the boy gets older and starts having nightmares about what happened to his mom.
harry is raised in the wizarding world, with the most protective family of anyone he’s ever met, and invites ron and hermione over to his house during the summer and somehow padfoot always gets them into some sort of trouble.
when harry goes through hardships at hogwarts, he always has his dad to turn to. james would stroke his hair back from his forehead and kiss his son’s scar and remind him, “your mother was the most brilliant witch there ever was and she’s watching over you, so you’ll never have to worry.”
even when pettigrew comes back and revives voldemort, james is on the quidditch pitch the minute harry comes back with the cup and cedric’s dead body, remus and sirius right behind him and swearing he’ll destroy anyone who doesn’t take his son seriously.
the fight at the ministry harry’s fifth year, james would remind sirius to keep focused, remind him not to get overwhelmed with adrenaline and to focus, and would watch not just harry’s back but his best friends’ too. when he sees sirius too focused on making fun to notice bellatrix amazing a curse straight at him, he dives in front of it to push sirius out of the way and ends up in St. Mungo’s after the fight, a little bruised and battered but with promises that he’ll heal and a sheepish apology from Padfoot in the former of an old, drool covered chew toy.
when harry disappears seventh year, he and james keep in contact with the magical mirrors that belonged to sirius and james paces the kitchen every evening, listening to potterwatch and shrugging off Sirius’ shoulder on his hand telling him that their boy will be okay because he’s incredibly smart and incredibly brave and honestly mate how’d you make such an amazing boy?
and then the fight at hogwarts happens. remus and sirius have each other’s backs and james just wants to find harry. he does, a little too late, being carried out of the woods in hagrid’s arms. he breaks down and drops to his knees and remus and sirius look at each other and think, “there is no way we can fix him after this.”
but then harry is back and voldemort is dead and james’ face is tear stained and they’re all worn out and bruised but their family is alive and sirius, a little hesitantly, offers, “…so who wants ice cream?”