I feel for your family, Susie. It must have been very traumatic for them all. But, this has been a long time coming and they (and you) have done all you can for your FIL. The time has come - and you all realised that - when you have to hand over his care to the professionals.
Your FIL gets angry and that, unfortunately, is often part and parcel of progressing dementia. My sweet, very religious cousin suffered like that. She would rant and rage, throw things at people, and swear at God, using words the family had no idea she even knew.