I live in MA and my brother lives in NC. He will be driving up for a visit some time next year. I want to offer the car rental as a gift. I would pay for the entire rental and It would be my credit card that you would have on file. Could I do this?

Yes you can, but speak with the branch manager and get everything in writing in advance. The only problem you might have is the type of vehicle because the rental car store has the right to give you something close or similar.

Best to call on the phone and ask.

Sure but you can do it one month before he comes.

Call the branch manager in your town or better yet go by the store.