Wow, he really is a sulker. (So was my dad.) Someone rebuffed him a lot when he was a child. That quote of his you just gave is really him talking to someone other than you. Maybe one of his parents was always telling him to stuff it. That's who he's really talking to.

Don't buy into "his" beliefs. Has he ever had a pet? I think he might benefit from adopting a puppy. His attitude sure is dreary.