Terrible photo! NOT a rattlesnake- look at the pointy tail, there's no rattle. Would help to know what state he's in- many things it could be, but all are harmless, so tell them to chill!
Sorta thinking Great Plains rat snake, btw. (they're a close cousin to corn snakes) Tell them to check local guide book (online thru Fish & Game for their state- should have pics to help identify). DO NOT HARM IT![]()