Same way as he did.
For valid medical reasons aisle seats are very important to me (want to talk about "frequent trips"?
)... so I go to some lengths to ensure that's what I get.
(And BTW if I can't get one I "suck it up" - I don't expect someone else to move for me)
I realise there may be slightly more sympathy deserved in this particular case.. (poor english etc) but I cannot see how
any of it is your friends problem either.
Sorry.
Perhaps I have become cynical about ANY swap request after being asked - more than once- to trade an exit aisle for a rear middle (or similarly ridiculous "trade").....