Is my sister-in-law being selfish about inheriting my in-laws’ house?

My husbands grandparents recently passed, leaving us with there house. There house is lovely but very outdated and needs a lot of work. My husbands parents live 2 doors down. They have a beautiful 4 bed house with a massive garden. Its all very modern and spacious. My farther in law has dementia and he's unfortunately gonna have to go into a care home as its too much for my mother in law and her learning disabled brother to cope with now as he's getting violent and suffering from seizures now its only fair now but we let the professionals care for him now.

We came to the idea but we'd move my mother in law and her brother into there parents old house and myself and my husband buy my mother in laws house as im pregnant and it better to raise a family in her house and be two doors down incase we ever need each other. Plus the money we buy her house for she can use to fix up her parents house for her and her brother to live in.

We all thought this was a great idea as a family but my stister in law who lives in Manchester which is a hour and half away from us is kicking up a fuss once again. She always said when she was younger she wanted her parents house but that means nothing. She has no children and she says she doesn't want any either (thank fuck) its literally just her and her boyfriend and her many different animals.

They can barely keep up on mortgage payments now because they live on the never, never and constantly beg family for hand outs. I said what about her work in Manchester and she said shed commute and that house was promised to her as a child... like wtf.

They honestly make that house disgusting if im honest and why does childless couple who barely have the money to up keep the house want a big 4 bed house for.

They also said its not there fault me and my husband work full time and have savings because they went bag packing and only work part time.
Is my sister-in-law being selfish about inheriting my in-laws’ house?
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