First off, I am so sorry that happened to you. That sounds super stressful and I would have been very flustered as well if put into that situation. My guess is that you still have a chance at that school, just maybe not in his particular lab. From the sounds of it, you wouldn't want to work with him anyways as he seems like a jerk (Side note: why would they say that you're not qualified to get a PhD when they're the ones who invited you to interview? Seems like more of a mean comment than genuinely trying to see if you're a good match).
The only advice I can give you is that when they ask you hard questions like that they're trying to see whether someone knows the hard work that goes into a PhD and has confidence in what they bring to the table. Another thing to think about is that sometimes the interviewers ask the hardest questions to the people they think are most compatible to work with them because they're trying to narrow down who would be best. I think you should ask to read the letter from the other professor (if you didn't waive your rights to view all application materials while submitting your application you wouldn't even need to ask them to send it to you) because you need to know what they said in it to make him say that. It may be too late in this application season to change your recommenders but it's good to know if you need to apply again in future years. Don't get too discouraged! I hope you have better luck in the coming months.