Identity check?

My son had a letter a few days ago about UC. He filled in a form on line with out telling me so I don't know what was in it. He has MS and can be a bit 'dozy' at times.

The thing is he's informed me that some one (who?) is coming here (home visit) in the morning to 'identify' him and it will only take about five minuets. I think this is a bit weird.

I have never heard of this before can anyone reassure me this is normal and not some kind of scam.

A quick up date.
A very nice lady from the DWP came to check his identity arrived when she said she would and was here about ten mins. She checked his name on the bank card, a letter from the NHS and also asked his previous address. And that was that, she said it would be sorted around the 6th of March and he would
Painless so far
Thank you for your reassurance yesterday.