9/11 Truther Building 7 Argument

[GrandizerII]

I had an argument recently with a close friend about 9/11 Building 7, and how he believes there was no way a big building with steel frames could've collapsed by a small fire, coming up with what was clearly pure ad hoc to me dressed in pseudoscientific jargon and embellishments. Not knowing what else to say at the time, I just pointed out that the science suggests it did, which he simply handwaved by saying that's not true. I had no laptop in my hand, and not enough knowledge to counter what he said with all the technical stuff one should know in response to those claims (which I stupidly told him only to be used against me), so what do you reckon I should've said in response as a layman without access to photos, videos, and publications at that time?

Argument ended quite sourly and got a bit too personal by the way. Not too happy about it. Maybe I should stop getting myself into such debates for next time and just quickly agree to disagree before things escalate for the worse.