Dear Dicky,
I don't believe they can, but much depends on if he has worked more than twelve months for them. As has been said, it is important to see what the COE states.
As had been suggested CAB is a good route, but there is also ACAS who are excellent and would advise definitively - you will find both numbers in the 'phone book (or from Websites).
Hope everybody get's better soon.
Regards, Bernard