You can’t do this! You cannot use IRA money to benefit yourself or others without the withdrawal being taxable. And your sister can’t make payments into your IRA!
There are self-directed IRAs that allow you to make alternative investments, such as real estate. BUT there are strict rules about the kind of assets that can be purchased, and it gets extra complicated at the point you need to make required minimum withdrawals.
Forget this idea — it won’t fly!