i cant sleep knowing I will leave my cat for 2 weeks

Im going on holiday and I have to leave my cat for two weeks at my mum's place but I know she won't take good care of him at all...
She has a cat herself and she doesn't even look after him properly, she let's him out and he has been lost before, my cat hasn't even seen the outside in his life 😰
I'm stressing so much, I can take him to a cat hotel either because is so expensive, even a cat sitter is so pricey...