I'm probably uniquely placed to offer insight on this game, so I'll detail my thoughts turn by turn where applicable.
Turns 2 through 3: Seeing +1 Suicune Hydro Pump chunk Snorlax for 44% immediately tells me this is offensive CurseLax. Alarm bells ought to be ringing in the Mum's head that boom is likely imminent. This being so telegraphed, however, puts you between a rock and a hard place. Boom pays off here, but it's an inherently risky play that could have spelled disaster had Mum read it and switched to Gengar. A turn-one or turn-three Registeel switch threatening Thunder Wave was probably your safest play.
Turns 4 through 6: Going Breloom here was a serviceable gamble. Establishing sand here was likely the play and obviously would have just accelerated the sequence subsequent. Seeing Breloom signals, and ought to have led Mum to anticipate, Pursuit support. In a lead or double-KO scenario where PhysGar and Breloom face off, Focus Punch is the natural punish for the expected SuitTar or Houndoom switch-in. That's a misplay on Mum's part. Given the information available once Gar revealed Destiny Bond, trading was probably the right play.
Turn 8: Here, if you know, you know. I imagine Dazi clocked it here.
Turns 9 through 11: I see the logic here: burn Fire Blast PP and let Zapdos eat a potential Toxic over Salamence. Either line is defensible. Double Protecting on turn 11, however, was ballsy, to put it mildly. A 50% chance of fainting to burn two Fire Blast PP feels far worse than simply accepting the 10% burn chance on Salamence (That said, the latter is arguably game-ending). You're in an unenviable position either way, and considering the game as a whole, it may well have been the right play.
Turn 17: Sacking Zapdos was objectively your best play here. Well played, imo.
Turns 20 through 21: This is likely match point, and juggling every line and probability here is a headache in itself. There are about twenty ways this could've played out given imperfect information. Suffice it to say, your safest bet was hard Loom. Salamence ought to be preserved, and the odds were against you if you stayed in. Booming Registeel here complicated what was already an awkward position.
Turn 26: This position is pretty clear-cut. You had to go to Loom. Lax was nearly certain to Curse, and staying in and letting it snowball was the only clear "choke", but describing it as "incredibly bad" is being far too harsh on yourself.
