how old is you're dad? Are you in the UK?
although I've not experienced such behaviour with my Parkinson's, I have with my own dad who has altzeimers, he doesn't have Parkinson's. He also has a vitiman b deficiency and has injections for this. any underlying infections make him worse.
also, if you are living in the UK and experiencing the recent heatwave....he may be a wee bit dehydrated.
i think i would be careful not to presume that everything is down to Parkinson's.
i hope this helps and that you get dad sorted.