How do I compromise moving out with my partner?

I have been with my boyfriend for almost three years and I just recently landed my first full time “real” job. I make more but not enough to move out on my own so I plan to save for two years and hopefully gain more experience to a more advanced job.

Anyways, he has helped pay the mortgage to his mom’s house since he was 17 (he is 24 now). His name was going to go on there but he was underage and they never got around to it. Anyways, his mom moved out and got married. So he had the place to himself but his two older sisters moved back in because one broke up with her bf and the other has been with her bf for 10 years but has no interest in a higher commitment I guess. This was a year and half ago

They show no signs of moving out anytime soon, I see them there even in the next 5 years. Both have full time jobs and make around 40–45k. They just pay gas, electric, water, and cable/internet.

I asked my bf if he would move out in two years with me but he’s worried about money. He said he would consider it. I’m afraid his sisters will be burdened with paying more money for bills and he will feel bad for “leaving” them. I don’t know how much it will hurt them. I’m a bit worried about money too that is why I don’t wanna move anytime very soon.

I mean would you help them pay for the house if the house was going to be under your name? If it stays not under his name just walk away?