Need help parsing a sentence containing s triple negative.

I was talking to a friend today who was discussing an interaction she had with her boyfriend. They were discussing their relationship and the next day while debriefing he said, "I'm just glad you weren't like, 'OMG he didn't not not say it, I'm mortified!"

Presumably did he respond in the negative or affirmative of saying "it". So high school but I can't decipher this or even decide if it contains enough grammar to make sense. It begs the question, why can't people use plain English?

Thanks for the opinions, in advance.