Can I move in with my Nan

As many of you may have read I have had to move back home and have been helping care for my Mum and Stepdad but I have a feeling I am about to be stabbed in the back.

My Mum may not be able to manage stairs so wants a bungalow, they will either go through the council or private (LHA) despite bungalows seeming to be more expensive. Now apparently my Mum has said she would only get a 1 bed place from the council so that in effect may leave me homeless.

Now my knowledge tells me that getting a bungalow from the council is like nailing jelly to a tree as there are hundreds on the list for one and going private will cost a fortune if they can even find one. (I have had a look) so OT from the hospital or social services are more likely to opt for adapting the current house.

If I move out I would be entitled to a room in a shared house which again are few and far between due to LHA changes. I have a few questions....

If I went through the council would I be paid full rent on a 1 bed flat/studio flat?
Could I move in with my Nan without it affecting her, she is in a 3 bed council house and receives some HB towards it?
If I found another person and rented a 2 bed house would LHA apply?