I'm so terribly sorry for your loss.
I'm no kind of internet expert, but I do enough trash reading on news sites to know that even celebrities with
PR firms, lawyers, and big bucks can't get photos removed from the internet. The internet really is forever, unfortunately.
Those who knew and loved your son know there was much more to him than one photo and those who didn't know him probably won't search and their opinions don't matter anyway.
My deepest sympathies to you.