Sibling relationships

Does it sound like he’s lying about how he messed up the car? Could he have been drinking and driving? Ok so my brother lost everything he had and fell on hard times. So my husband and I let him come and Stay with us. I don’t work so I was letting my brother use my brand new car to get to and from work. Well my aunt has an extra car it’s sort of a POS so they let him use it recently. He went out with a male friend one weekend and claims he accidentally hit a curb in the car and it needs a new radiator. Is that even possible? He’s been arrested for two DUIs before and I honestly feel like he may have been drunk and actually ran full onto a side walk. I’ve sort of hit curbs before when making turns, but Just my tire hits it. Now I’m second guessing him and I don’t want to accuse him of something he didn’t do but this determines if he will get to use my car again. What do you think?

Edit : it wasn’t my car it was my aunts. I only let him use mine for work. She let him use hers to go out during the weekend