Firstly my condolences for the situation you are in, I understand all too well.
Technically, no, there is no means for the existing account to be transferred to your Grandma, while your Grandpa is still alive. What you need to do is to get someone else, yourself or your grandma to obtain Power of Attorney over your grandpa’s interests, it doesn’t sound as if it would be too difficult to arrange this.
Once done then this person can negotiate with VM as if they were the account holders (now VM will need a copy of the legal documents first), VM are legally obliged to do this, no arguments!
There is another, legally dubious, but nobody is ever going to kick off about it, do you or your gran happen to know the details for the account, account number, address (well, yes, obviously you know the address), memorable word (probably not), the email address associated with the account and the password? What I am getting at is this, if someone else were to call them and ‘claim’ to be your grandad and had enough information to pass their security, then how would they know?
