moving in with partner

Hi, I'm planning on moving in with my gf quite soon but was wondering how this will affect her benefits, she currently gets a small amount towards her rent and some tax credits to top up her wage.

My house is mortgaged but in negitive equity so needs work doing to it to bring it up to value to sell, I was planning on doing the work after I have moved out so it is easier with empty house.

The question is will her benefits still get stopped even though I will still be paying my mortgage until my house is sold ?

Thanks in advance