I need advice regarding my Dads PIP, ESA and housing benefits

So my dad receives the above stated financial aid, and hes recently been informed of an ESA performance Measurement Visit, and hes contacted me concerned that he could lose his aid or be accused of committing benefit fraud unknowingly because he sometimes receives money given from his mother of anywhere between £50-£600 monthly, for various reasons ranging from buying people presents on her behalf, or sometimes just as straight up money gifts for him.

He also has quite a large number of collectables such as blurays, horror movie memorabilia etc that will be present in the house hes being interviewed in, all has been purchased either using the benefits, or the money received as gifts.

Does anyone know if there will be a legitimate risk of him losing his benefits based on that information?

**edit, he lives in cumbria/north west UK