Father/son Penis Pictures Should I Report This?

Should i report this? - father/son penis pictures

My children (son's father is 17 months) has the diapers of our children, when I changed for a visit with his father (we are not together) and his father had been wiped and with our children played with his penis and laughing, not just once or twice been constant and has about 7 times. I was shocked and found it very disturbing. What should I do? His father is a bit mental, so I'm not with him. and supervised visits with her sister, she was there with my eyes.