>He should not have the kind of relationship with an AI that would enable discussions to turn into arguments.

There doesn't need to be any kind of special "relationship with AI", parasocial or whatever for discussions to turn into arguments. Regular use can turn into that just fine, and this is also what they describe.

Imaging something:

P: I want to figure out the best mortgage terms given these parameters (...).

C: Honestly, renting would be a better financial choice than buying.

P: That's not what I asked. I'm not asking whether I should rent or buy—I'm asking about mortgage options.

C: But you asked for the best option. If renting is better than buying under these circumstances, then a mortgage isn't the best option.

And so on...