Thats a touchy thing. I have repaired things for relatives, and wouldn't take money. I don't want a relative as a customer..........nightmare......... But I don't think it's right for him to charge you, unless you knew before. I ask for help from my son when I need it and he helps. But, I want him to replace the ductwork in the house, and I can't help, so I'll give him somthing even though he said he would do it for free. If you have already paid him, just let that one time go. If you need him to fix somthing else, ask what's it gonna cost you. Then that might be the right time for that discussion. I have known guys that when they do what they do for a living they expect to be compensated. I personally would never ask my dad for money. If I couldn't afford the part I would tell him to get the part and I'd fix it for him. I owe my dad alot and couldn't stand myself if I treated him like a paying customer. And as far as the garage goes, If it wasn't like I left it, it would be the last time he used it.......................... Period.