Wedding money

Soo my dad has never been in my life. I know who he is and everything but he has chosen not to visit etc and maintain a real relationship of any kind, other than a few social media comments. I’m getting married this year and he has out of the blue sent me £3500?! He never paid child support etc when I was younger. He will not be at my wedding as he doesn’t deserve to share that day with me after everything. I want to send it back to him but part of me feels it’s a tiny part of what he has owed as he has never contributed in my whole life. Help please!