He has been a junkie for the last 30 years. He was always an untalented standup that relied on shock humor and fame from the Stern show. Great radio sidekick for the most part, although when he was really fucked up he was often annoying as fuck and really chatty. He was pretty good on Dirty Work too I guess, but that movie was mostly all Norm and Farley in his small part... And Rickles.
His life story is basically: junkie who happened to be quite good on the biggest radio program on earth for 7 years or so. But Howard made a lot of talentless people look good so I don't think it's THAT much of an accomplishment either. His radio show after was shit.
Howard created a world where people deeply cared about the characters on the program. So it became a thing for people to hope and pray and wish that he was happy and stayed sober. People cared about his love life, his family life, etc. And that carried him through his standup gigs and life after Stern. But at the end of the day, he's a junkie and always has been.