BGII:EE modded Irenicus Hell battle bugged

Dear Community,

I've reached the last fight of BGII, the battle with Irenicus in hell. My problem is this: He won't die. I have an SCS installation with ascension, installed via big world setup. Game version is 2.3. I also modded BlackRazor with near infinity, including it's description. Could that have corrupted dialogue.tk? I also installed the improved hell trials mod, that didn't work though (I still change alignment, even if I only do one evil thing), maybe that is the problem?

I tried killing him 5 times now, so it doesn't seem like a one time thing. The pit fiend he gates in after a while has some very buggy invisibility. He sometimes seems to trigger scripted "contingencies", activating a few spells in a row. He also gets some "dialogue" lines about how he cannot take it anymore (not actual dialogue, those lines above his head and in the event log). I even managed to kill him once by mazing him and setting spiked traps. But no matter what I do, I cannot trigger his cutscene. I really don't know what's going on

Do you know how to trigger his death cutscene by console and advance the game?

Thanks in advance!