@Sonia158 it is quite often standard procedure to have a meeting with HR. Where I work mine were to discuss how I was getting on, if there was anything they can do to support me & what he chances if me returning to work were. They also wanted to see occupational health advice.
I would make sure you understand the works absence policies - if you don’t have it ask them to send you a copy. I would try & get someone to attend with him - a TU rep if he has one or a colleague. We aren’t allowed a relative but that may be different whete your hubby works.
Speak to ACAS for advice so you know your rights.
Ultimately employers can let staff go but must have followed the correct procedures. My advice also would be to let them dismiss him, at the appropriate time, & don’t let them push him into leaving. Where I work ill health dismissal comes with a small payout- not sure if that applies everywhere as I think it is tied into the pension scheme.
But as I said at the start of my post it is normal for employers to hold meetings with absent employees. Hopefully it is a fully supportive meeting but arm yourself with advice just in case. Never any harm in being prepared. I think I had 4 or 5 meetings when I was off but I knew the policy better than my boss so was fully prepared for each one 
Hope the meeting goes well.
Best wishes
Ann xx