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.