Understanding rare disease?

My nephew whos 42 and his 4 sons have a rare genetic disease called Multiple Hereditary Exotosis also known as Hereditary Multiple Exotosis. The main part is that extra bones and spurs grow where they shouldn't due to missing Heparin Sulphate in his cells. So there is a risk and fear that these can become cancerous tumors. These extra bones can cause damage in the body to muscles and nerves and can only be removed by major surgery. He didnt grow strong and is small in stature so hes not strong and struggles with manual work for long periods of time. Plus because of this genetic disorder it can cause other illnesses such as problems on the gut, lungs, neurological and many others. This leaves my nephew with pains and extreme fatigue.. hes tried to work in the past but ended leaving his job because of the pressure and the way his bones grew in his feet caused too much pain and became completel numb to where he had to put them in hot water to get the circularation going. Now claiming Universal credit and on top of this has symtoms of Long Covid after getting corona virus early last year.

They all overcrowded living in a private 2 bedroom terraced house with damp and mould and its so cold. He's is so worried once job search expectations of Universal Credit will come in to effect that he will lose it as he is now too poorly to work and worried about what benefits he can claim when this Rare Disease is not recognised, not understood and is invisible to many.. if anyone out there that could advise and help It would be so appreciated. 

Noreen ?