Is it a good idea to buy my mom's house in Carson, CA?

[Vanessa Estavillo]

The situation:

-My parents are divorcing and want to sell their 3bd 2ba home but still owe $470k on it. According to zillow, it's worth around $535k, someone has offered them $550k 

-I would like my mom to be able to still live in the home, so I was considering trying to pay my step-dad off so he can move out

Should I:

-Try to buy the house from them for what they owe the bank ($470k) and give my step-dad his share in cash?

-Is there a way to put the property under my name/share the title with my mom instead of "buying" it? 

-Try to turn it into a duplex, each unit would be a 2bd 2ba?

Any and all suggestions/advice are appreciated!