Sounds like BF is unable to recognise basic social cues and needs to be parented - which will make him a selfish, unreliable and not fully adult partner in a relationship. He sounds to me as though he’s stuck at the developmental stage of a 13 year old boy, for whatever reason.
The normal thing to do in the Xmas circumstances would have been to go shopping together, or at least ask what part of the meal he should have provided.
Not helping with the cooking suggests he assumes he will be cared for -‘parented’- and does not recognise the responsible, adult, participatory role he is called on to play as an adult in a relationship.
Not having oven shelves suggests he doesn’t look after himself & doesn’t see the need to.
Keeping his box of chocs unopened while everyone else offered theirs is failing to see & react to a really obvious social cue.
The unreliability about the mattress suggests he does not understand that people will remember & rely on what he says. The rudeness about it (the cat comment) suggests lack of maturity. Really not an adult’s response - this is a 13 year old’s comment.
The grandiose promises about the future without any serious planning similarly sound like something a young teen or child would say - without any real thought or detail - without realising in the adult world this will lead to reliance.
The framing of the hot chocolate as a ‘treat’ is childlike & not something you’d expect in an adult relationship.
I would say there is something more significant going on here, about his social & emotional capacity & development, & that unless he’s willing to address his difficulty with social cues, & immaturity, and unless you are willing to take on the (possibly very unrewarding) task of helping him do so, it’s time to end things.
And the idea that ‘love keeps no score’- the mantra of abusive & exploitative men everywhere. Don’t fall for that crap 🤢.