I get where he's coming from with his thinking, @SqueezyCheesyPeasy but, with anxiety, there's a huge risk with the throwing in at the deep end approach resulting in panic attacks and breakdown.
With anxiety, difficult situations must be tackled in baby steps. Getting totally comfortable with each little bit before progressing.
So, if he possibly can let his flatmates know he does struggle a bit at first and he probably won't be in the kitchen right away, that would be good (often there's a flat whatsapp chat and he can pop it on there - students are very friendly and understanding about these things )
Then he might be able to set small challenges - come out of his room and listen for noise in the kitchen, then return to room.
- move to kitchen and peep in if no one there.
This sort of gradual exposure can be effective.
But i do think if he gets home of a weekend, the whole thing won't be so overwhelming and he has a 5 day countdown, which breaks things up a bit too.
If he's coping, he can stretch this out.
The risk with going at it full on, pushing himself right out of his comfort zone big time too is that, if he realises it's too much and comes back to live at home - or retreats to his room shut away, that almost validates to his subconscious that the kitchen and people are very frightening and he must stay away. That sends the adrenaline levels sky high and he will get those panic symptoms next time he tries - palpitations, frozen in fear, sweats, dizzy, sick etc.
So - gentle baby steps with his difficult areas. A uni counsellor could help put a plan together with him and check in to see how he goes with it.
Good luck for tomorrow!! Really hope it goes well for you all!