archie
This sounds like a Right Payment review, the DWP select a random number of claims to be reviewed each year to ensure that the claimants are receiving the right amount of money.
I'm surprised that they are doing these during the current situation but if they are then there is no way to avoid the call.
If your father is unable to manage the call then you should contact the DWP to see whether it can be deferred or whether you can attend as well to answer on his behalf.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
