I believe that Bucky has got a credit with BA for tickets that got cancelled last October because of COVID. So he would likely still try to use that up by buying coach seats and then trying to upgrade them with his uncle's miles... I don't think that the uncle using miles to book award tickets for them is going to work because they'll still be stuck with the credit that will expire if they don't use it....

So is he likely to be able to use the uncle's miles to upgrade coach tickets that he needs to buy with his credit with BA? It seems that the upgrade availability just a couple months out is going to be a problem too...