Hi, as Fred says, it's a case of giving it time. After some time has passed, these bad thoughts will fade a bit.

Sometimes in our lives things happen which are hard to cope with. Your in laws suffering is over now, and it sounds like it was quick, where it could have been a long decline :(

It is maybe the feeling of not being in control which is hurting you, I don't know of course.

It's time though. I am using personal experience of how I dealt with bad things - take up a physical activity, cycling or running, dig the garden over perhaps.

Hope things get better soon