Barclays won't update address

My brother sold his house in 2009, having been widowed four years earlier, and went off travelling abroad with the proceeds. Not having a UK address any more, he gave my address as a 'care of' address to his bank and his bank statements arrived at my address each month. Two years ago he married an American woman he met on his travels and they both now live at her home in Texas. Both my brother and myself have informed Barclays on several occasions that he is now permanently residing at his wife's home in Texas but they refuse to update their records. They have also refused to send him a new debit card. Their reason for this is that his signature looks different to the one he had years ago when he opened the account. They can see from withdrawals that he's been travelling and is now in Texas. They have said he will have to sort out the matter when/if he returns to the UK and can go into a branch with ID. Is this normal...?