The guy had a lot of fun, she was gorgeous and very passionate about sex. As they say in our well-known proverb: "If you treat me like a human being, then you should treat me with all your heart! Except that when he fucked her in the mouth with a big black cock it was a little difficult, but otherwise - it was only for fun!
Considering the condition of the grandfather's device, I do not see anything surprising that the granddaughter let him clean her hole (I would even say, she begged to do it herself, apparently it itched a lot).