Oh what a cutie!!
Glad he's okay and his owners are happy to have him back!

I'd worry about not having a fence around the pool, I'd feel horrible if an animal or person died in my pool. (I know you said you don't have any small kids near by, but you never know)
I understand it's not up to you, but if I were you I'd bring the idea of fencing in the pool up to your parents before something very bad happens.