Sports club have said my husband isn't eligible for a membership discount despite being diagnosed with blood cancer. What can we do?

My other half is a long time member of a sports club, all members participate and can compete in tournaments. He was diagnosed with a blood cancer last spring and has just finished his 18th round of chemotherapy and could be on this treatment for years.

I’ve been lead to believe that anyone diagnosed with cancer is automatically classified as disabled? Which should qualify him for a discounted membership fee at his club but the management has said that he isn’t eligible. But I think that is wrong. Does anyone know what he can say about this topic to his club management?