I've known three that died before 15 from Melanoma complications, including a GP jumper. But also known as many with no issue....including the 32 year old pony who is my babysitter for the youngsters. Sorry about your horse, it can be heartbreaking to deal with it.
Personally, I've owned a few Gray horses. I have one gray OTTB (she was free). But not my ideal color...as it is PITA to keep clean. As a show groom though...the black horses were the WORST. They showed every line when clipping...and showed every speck of dust. At least the Gray horses once cleaned looked clean even if they got a touch of dust on them from the warm up!

