Call from decision maker

In the past we have had the call from the decision maker saying the claim failed for reasons XYZ. They ask if there's any other information we can add to the claim before arriving at the final decision.
At the moment I'm ' unofficially' (in their eyes) the representative.
the family member I'm ' representing' suffers from severe anxiety with stress so if confronted with a phone call from the DWP decision maker, assuming they do of course, can they ask them to call back at a time that i will be present so they can answer the questions they may have? it would be the same day so not being evasive.