So this dude ignored your pointing out that he was treating the DM and the other players like NPCs and derailed you into a discussion of whether the game was “really” D&D or not?
Your problem is not that he has unbalanced characters or bad tactics. Your problem is that he’s a bad player who thinks everybody else’s only job at the table is to make sure he has fun.
I know you said he apologized, but he needs to Get It, otherwise as soon as he gets bored he’ll be right back to playing Sir Poutsalot, Ruiner of Tactics.
It's a sad case of living in the past. For 35 (I think, I only started playing with him in '91 or so), he's had his own personal campaign setting, and he's very comfortable with his AD&D game (which includes both 1 and 2e, whatever basic D&D he likes, and some elements of Traveller). He has convinced himself that his house rules are the actual rules of the game, and, sadly, any deviation from this model of D&D "isn't" D&D. Back in 2000, he visited a hobby shop that was having a D&D rollout, and immediately took umbrage with the removal of Thac0.
I used to feel bad for him, being a "forever DM", but I've kind of noticed over the years that any time the question of "who is going to DM" comes up, he jumps at the chance. Ten years ago, another friend (we'll call him friend B) I hadn't seen for awhile invited me to his place for D&D, said he was going to run, I told him what I wanted to do (a very offbeat Gnome Fighter/Cleric, because I know his gaming style is super laid-back). I showed up, character in hand, and oh, he's not DMing now, friend A is. Friend B's campaign has never materialized, and friend A constantly pesters me about what my Gnome character wants to do in his campaign, even though I've been basically his only player for at least 5 years now (friend B had some life problems, preventing him from playing; I've been really wanting to wait for him to come back to the table, because friend A simply. cannot. stop. presenting new plot hooks and problems for the campaign world that he thinks I can stop- I can't, any time I sit down to play and say "ok, let's deal with X", I get bombarded with new plot developments!).
A comment upthread got me to think back, and I realized, he has always been super critical of other's DMing styles. If he recalls a past time he got to play, he always talks about his character, and never any positive beats from the game. I really didn't notice this, because one of our other DM's, his nephew, read the 1e DMG, learned all the wrong lessons from what Gary was saying, and is known to be among the most brutal, cheapskate, "DM vs. players" guys I know (when he runs), but gets real huffy when his own characters aren't the stars of the show, lol.
It's so bad, that when he talks about his favorite character, "The Boss" (a veritable idiot savant who declared himself the party leader due to his high Charisma), he has completely forgotten who the DM for that campaign was! (It was a-me!)
So yeah, maybe he does what he does because he's pre-determined that he doesn't like other people in control, and plays the clown until everyone realizes he's the only competent DM? I really don't know. I really hope that's not it.
I think I may have undersold exactly how disgruntled he is that the group isn't interested in playing AD&D after our attempt (2 sessions, and as I said in another thread, if one whole session wasn't basically character creation and explaining rules, I'd be amazed). I talked to him yesterday, and he was still on about "Why can't they see how terrible this WotC edition is?"
"Which one are you complaining about? You balked at 3e, and I couldn't even describe to you what 4e was like without you going off on a rant about how much you hated 3e. It's been 23 years, you have to let it go!"
Anyways, we'll see how the next session goes. After talking to the DM of our current game, I wonder if the Bard's new antics aren't a reaction to Friend A's own shenanigans.