Buying a house with a parent

Apologies if this is in the wrong place, I wasn't sure which section was best to post in

My father has recently passed away. My mother is elderly, in good health but she doesn't wish to live alone. I would like her to live with us but our home isn't large enough. We have spoken about it at length and the ideal solution for us all would be for her to sell her house(value approx 300k), us sell our house(value approx 300k, equity of approx 140k) and for my husband and I to take out a small mortgage (approx 100k) so we would have a total pot of approx 500/540k. Plan then would be to buy a house with a granny flat.
What are the things we need to consider? I'm not sure how things should be structured? Am wary of having half of our new house in her name in case nursing home care is needed in the future (hopefully not but none of us can predict the future) but not sure what the tax implications are if she wasn't named as an owner. She is not concerned about being named.

I'm an only child so there are no other siblings to consider.

We will obviously be discussing with the solicitor but we're still only at the discussion stage and I'm trying to get my head around what needs to happen. Any advice appreciated.

There is no simple solution and every solution has its risks.

A) The simplest solution is for her to sell the house and give you the money but I would strongly recommend against that because of all the things which could go wrong. Of course, you think that nothing can go wrong, but here is what has gone wrong in similar cases.
1) The couple owned the house jointly and separated. He claimed that the mother had given his wife and him the gift jointly so wanted half the proceeds of the house. Kerching for the legal profession.
2) In another tragic case, the wife died and no problem at all the son and mother in law got on very well and continued to live happily. Until he met a new person who not unreasonably demanded that his mother in law leave.
3) Your relationship with your mother changes when she comes to live with you. You resent her spending every evening in your house criticising the way you raise your kids.

B) The best solution is probably that your mother sells her house and lends you the money to buy the new house.
Hopefully, nothing will go wrong, but if it does, at least your mother has an asset.
If you split from your husband, he can claim only half the equity.
If your mother wants to leave, you owe her €300k

C) Your mother continues living in her own home and takes in a young student to live in the house.

Brendan