Your mom has research to do. Check rules on her 401k with her employer ( vested, not vested) and with her accountant.
If she takes the money out and puts it in her personal checking account that will be considered ordinary income and she will owe, state and federal tax, plus penalites and maybe SSI. So, she is going to lose a massive chunk of money. Like half. So that is not really a plan.
It is possible that she could create a self directed 401k and that could own real estate. But, she could not do any transactions with family members so that doesn't help you out. Also, much harder to get financing and she still can't take out any money before she is of retirement age. Also remember that she isn't paying income tax on these accounts so there are no deductions.
She might be able to take a loan against a portion of her 401k and loan some of it to you but you need to research that. Also, not good advice for any one to ever borrow against their retirement. If you both had self directed 401k / IRA accounts you could possibly invest together but you would need to figure out how she gets her money at retirement age when you can't get your money until retirement age.