A mortgage for a house for my mother to live in

Hey all, looking for a little advice.

I am currently in a situation where I own 50% of the house that I am living in, my mother owns the other 50%. Essentially my mother was supposed to move out with her partner and essentially things just did not work out as planned.

I am going to remain in this house with my partner as it is bigger and there is space available to us for what we are looking to do. My mother is not in a position to move out and afford a place of her own and to be honest probably never will be.

So mine and my partners thought was that we essentially get a second mortgage in both of our names (me and my partner - that means I will have 50% ownership of this house with my mother, and 50% of another house with my partner.) We can afford to pay out for the other property and we think we could get a mortgage to cover it. My concern is, am I able to get a standard mortgage for a house that we do not plan to live in, as long as a relative is staying there? We will be taking on the costs of the mortgage costs so we are not renting it, so a buy to let mortgage I don't think is suitable.

Before I contacted my bank, I was wondering if it was OK to get a house for family to stay in.

Thanks in advance.