Although not directly involved with your question please make sure your elderly relative has all their finances, internet banking ( especially passwords), will, Power of attorney etc sorted out before they leave the U.K. I have recently been involved with a similar aged relative moving Australia to U.K and it has been an administrative/legal nightmare. It took six months to get the admin sorted and I have heard tales that it has taken some people eighteen months!
Good luck
Rgds
AyrTC