What should I do if my grandfather (81) insists on seeing himself urinate?

I currently live with my mom and my grandparents. Just last month, my grandpa broke his arm when he fell off the bed after going to the bathroom. My mom, grandma, and I have been taking care of him ever since then. However, my grandpa is quite stubborn and sometimes refuses help. Whenever my grandma or mom tells him he needs to get up so they can help him keep clean (like washing his feet, brushing his teeth, washing his body/hair, changing his diaper), he always says "it's none of your business!" And the last couple of days, my grandpa insists on holding his penis and seeing himself urinate than just going inside his diaper. There has been two cases where his urine fell onto the floor. My grandma and mom would have to push his hands away in order to stop him from taking his penis out urinating all over the floor.