This is more legal advice, and you should really consult a tax adviser. I will tell you that I believe you are wrong in what you're thinking, and that it's actually you that would have the tax consequences (or loss of tax attributes) if you did this and it actually was a gift (as opposed to say hidden compensation for past/future services).

If you can afford to make that kind of a contribution, you really need your own professional advice regarding the tax consequences.

Also, if this is going to be a financed transaction, with just you lending your credit, perhaps a down payment and them paying off the loan, the answer would likely be different. And in that case issues besides tax liability come up. What I'm thinking of there is ownership issues and the fact that I really don't think people are doing other people a favor getting them into financial transactions that they don't qualify for on their own. The chance of their default is very high, and there's also a chance that their default will drag you down with them. So before you do something like that I'd again consult an attorney.