Deontay Wilder Says Tyson Fury's Coke Problem's No Joke

They've trashed each other for YEARS -- but boxing superstar Deontay Wilder is putting his feud with Tyson Fury on hold ... saying he truly wants Fury to get help for his cocaine problem so he doesn't die.

TMZ Sports spoke with Wilder -- who tells us the "real" Tyson Fury is not the monster you see in the media ... "He really is a good dude."

Wilder says he was really impacted when he learned about Fury's drug problem and suicidal thoughts -- and says he's even willing to fly to England to lend his support to his embattled rival.

That being said, Wilder still wants to beat the hell out of him ... saying, "We didn’t promote [a possible fight] this many years to be beat behind some kind of drug activity."

In the past, Fury has threatened to sexually assault Wilder.

Wilder said he was going to baptize Fury with his fists.