My husband’s job involves a lot of lifting, and when he suffered a back injury his firm’s medical staff said it was likely to recur so he was sacked. However when he went to see his GP he was told the injury could be fixed and it shouldn’t stop him working.
Your husband should have been consulted and given an opportunity to put his view as to the prospect of his recovery before he was dismissed. If an operation or physiotherapy can help he should notify his employers immediately: even if his injury is permanent they should probably have tried to find lighter work for him. It’s possible your husband will have a claim for unfair dismissal, and he may also have a claim against his employers for the injury he suffered so he should see a solicitor urgently.