OK - just got back on the case.
Are you SURE about the facts on the potential for redundancy 2 years ago? - as in you checked it with ACAS, CAB or wherever.
Did he get a letter from employer when all this happened? - if so, what did it say? - perhaps something like 'Dear XX, following closure of the site, I am not making your redundant but I am redeploying you to another part of the company. Clearly this isn't going to happen until you are fit enough to start work again at which time I will discuss with you the options for your work'.
If he didn't do something like this, I'm not sure, but I suspect your husband should have been able to claim that actually he WAS redundant - and hence entitled to payment in lieu of notice, or notice of termination of contract.
I'm not sure and want more time to check it - and the passage of time since may have altered things.
One last thing - did everyone else at the time of the redundancies get paid money in lieu of notice OR were they forced to work their notice? - it may make a difference.
A very interesting case - I've never heard the likes of it before.