TOD:
Well, I'm not sure. If I had free reign, I think I might look for a way to have a narrator do commentary to the audience in between the "unpleasant" scenes. Since Dubin, like Larry Hart, was very talented, that talent can be displayed to wonderful effect while the "true-to-life" stuff needs to be lightened with a commentary that suggests various ailments/psychoses that plagued the central character throughout his life.
For pity's sake, though, don't pull the stuffings out of the character. Look at the botch that MGM perpetrated upon Larry Hart's memory in "Words and Music" by making his angst a love sickness for Betty Garrett's character (and she wasn't buying into Hart in any way). So faux tragic.
Very much like the whitewash of Cole Porter by the Warner Brothers. But, I digress...