This is probably not a good idea. Have you sat down and set up a budget?

Assuming you have a better rate now, Can you remove your partner's name from the document without refinancing to that higher rate?

I think this would be unwise. Even with a roommate, that is not a stable arrangement for your future.

It isn't your responsibility to do any of this, or take care of them when they waste all their money. It's great if you try to help and they are receptive, but please don't feel responsible for them.

Ultimately what they do, or don't do, is their choice and theirs alone. Sounds as if your dad may ruin things no matter what anyway. With that kind of income, they should have no concern, so, if they're unwise enough to squander their fortune, they must manage the consequences.

I hope you can get them to speak with someone that can help guide them, tho.

Is your 16 yr old going to have a job to help pay for the car, insurance, gas and maintenance?