This is the first time FIL has stayed with us. I wanted to make his stay nice and comfortable and had a postive attitude towards him. I felt that he doesnt like to be told when he is wrong so I stopped telling him with regards to home stuff not my child. The hitting thing has just occured lately and I didnt want to make a scene of it when things are so crazy from before so I have spoken to my husband and asked what to do.
Next time FIL hits I will tell him off.
After having posted here I have realized that the main issue is that I due to my tiredness havent taken any stand and FIL has gotten more and more space to influence things.