Good Morning,
I would follow his lead and be supportive. I don't think I would say anything to soften what he says. Like "Oh that's ok" because maybe it isn't.
When my son talks I pretty much just listen because I often strongly disagree with what he is saying. I have stopped defending myself and I don't blame him. If I find things that are hurtful or offensive to me I can always try to change the subject or end the conversation. I am not a a captive.
Hugs,
JT