EVICTION

I am in a desperate situation and would very much appreciate any advice please. I am in receipt of State Pension and am having major surgery in 3 weeks so time is very much of the essence. Citizens Advice is open just two hours, once a week in my area. My son discovered he had a brain condition over ten years ago and had urgent neurosurgery to prevent paralysis. His symptoms have returned and as a result he has lost his job. His GP has given him a fit note for 30 days initially to say that he is unfit for any work currently. My son has also completed a PIP application as this is an ongoing, life changing condition. He is renting a one bedroomed flat from a private landlord and cannot afford his rent. He seems to be struggling with finding out what to do, particularly as everything is online these days. Can anyone point me in the right direction please? If he is evicted he has nowhere to go, other than my living room floor. With my pending major surgery and his feasible further neurosurgery this all seems very overwhelming for both of us! With many thanks!