Squeak – I am not insulting you. Perhap you have an irresponsible nephew, brother, – a relative who is not your child – who is deep in credit card debt, and you wanted to lend them the money to pay it off? Why is that obvious? You seem to be a generous sort. Anyway, I apologize. I was just trying to understand your shaala. Then the Gemara would apply; as far as chinuch – the Bris Yehudah writes at the end of Perek 2 that it would seem that for an adult (fiscally reliant) it would be permissible, and leaves with a tsarcih iyun. I suppose his safek is that still, you are teaching negatives habits to another Jew, regardless of your chinuch obligation them, and that is the point of chazal.
After you are matir neder, please tell us your psak.