Financial help for Family member with heart issues

Hi,

Hoping someone can advise
Family member had heart attack last year, has had to have the machine fitted to shock him should he need it (no pacemaker as he was told it wouldn't help and the damage is permanent). He can get around to an extent. But often has to leave work early as can't finish shifts and struggles. OH works part time and picks up extra shifts where she can but is not on a great income.

He has just been told needs a hip replacement which is very dangerous in his condition, but the alternative is he will probably end up in a wheelchair as suffers with it a lot. They're on council list as private renting at minute but want a bit more security as they're getting older and don't wish to rely on landlord not wanting to sell.

If/When he has the hip done, hes going to be out of work and unsure of sickness pay etc. Who should they speak to regarding any entitlement if he is unable to continue working? (He can't do it now to be honest, but he's quite independant and goes anyway, just often can't stay the whole shift). Noone I know really been in this situation so unsure what to advise them but want to help/find out info.

He does get a small pension but nothing near enough to let him retire (Mid sixties)

Any help appreciated. Whether he might be entitled/who they should speak to.