I don't want to help my brother get a motorcycle
Why do you not want to help your brother get a motorcycle?
Well, Joe is over 50 (he has had an accident 2 years ago, he had to give up driving. And I am the only one who can help him out). I checked with him personally and he said never mind for now. It's my decision to make, not his.
Family or not, you're not obligated. Let him know you're tight on money and don't have the resources to help him.
My family and I are very close and I can't just ignore him like that.
I understand, you don't have to ignore him. You can be honest and tell him exactly why right now is not the right time.