Even though she has 3 other children and 11 other grandchildren, she must trust you quite a bit to ask you to do the honors. Adding your name to all the accounts does the same thing as making you beneficiary - if she croaks, it's all yours.
However, you're right, you definitely want to explore the liability side of it, especially with real estate involved. It might actually be better for you guys to go in and talk to a legal counsel about what the best thing to do is.
I would imagine the best thing to do is for her to have a will, and a living will, that name you her power of attorney, which would give you decision making power over her assets in the situation where she's unable/dead. Likewise, with a will, she can choose to leave all those assets to you (if that was her plan with putting your name on things), or not, without there being any question because your name is (or isn't) on her bank account.
I'm not a pro, though. Definitely talk to a pro, together.