I don't think it's clear they knew about his drug use. From what i understand, he wasn't a regular at the meetings and had a girlfriend, etc. I doubt they knew what he was doing in his own home. Perhaps Larry Graham did, but no one else.
However, once the rumors & conjecture (including the perocet OD a couple weeks before) became public; the fact the memorial was still held at the hall shows clear preferential treatment (or valuing all the free advertising over losing face with members who see the inequality).