To not want to be a ft carer for FIL

[Shouldershrugger]

My dh and i moved into my PILs house to help look after them alongside dh sister. SIL is the main carer and dh helps out in the evening and weekends. I help out when I am available to. I work pt and have 3 children. Youngest one being 2 yrs old. Sil has been bitching about looking after her dad a lot lately and has been insinuating that she has been doing us a favour. She sods off every evening and every weekend. She gets paid for looking after her dad and her rent is excused as she lives in one of FILs property. Due to her bitching, griping and sniping at us lately, dh is going to talk to her and let her know that if she wants, she no longer needs to look after their dad and he would be capable of doing so himself. That means me looking after fil when dh is at work. Fil requires all around the clock care. He's unable to do anything for himself. Apart from feeding himself. Everything else is done by us. Aibu to not want that responsibility full time? I'm happy to help out when I'm home, but I want to have the freedom to go out whenever I want. Am I being selfish? I feel like such a cow.

To give you an idea of care costs, I recently had 24/7 care for my terminally ill father and it cost around 9k per month. This was in Essex. I was very lucky to be in a position to fund this and truly, it was worth every penny, not only to ensure he was safe and well-cared for but also for my peace of mind. It meant that although I helped out with actual physical care when necessary, I was able to spend his last months with him as his daughter rather than his frazzled and exhausted carer. We had quality time together and for that I shall always be grateful.