<human>: Could you distill the essence of the text into 1-3 sentences?

My Dad owns a house (possibly small mortgage, not sure) and he is retired with a decent and steady pension, around £23,000 a year. He has no debts and his house is probably worth £150,000 or thereabouts. Both me and my sister are mid 20s, with degrees and some student loan debt.

Could my Dad put down a sizeable deposit from the sale of his current house and pay 'rent' to me and my sister to cover the monthly mortgage payments?

My sister and I both work full time (me £23,000 and her £35,000) but we're both young, so our situations will probably change at some point. Neither of us own our homes, we rent. I want to avoid destroying my family with financial drama if anyones situation changes. I also want to do this great thing for my Dad, because he's my Dad and I want to support him. He wouldn't be able to afford a home where he wants to live because house prices are too expensive and he's a retired 65yr old so cant get a super pricey mortgage in his name, but me and my sister probs could?

Aside from the usual advice for first time buyers getting a mortgage (which I also know nothing about apart from a quick google search), what should I know?
<bot>: In my 20s and want to put my name to a mortgage for a house my Dad would pay the deposit and mortgage on.