loosing job after staying on the unpaid leave

Hello, last year I give a born to the twins. There were serious complicatios and I almost died. Due to this fact my husband decided to go for the compassionate leave. The emplouer showed understanding attitude  and he assured him that he will not lose his job (we have even the e-mail correspondention with the employer). What's more, my husband as the specialist was always ready to answer the phone from his former job and advise them.

Now, as I am able to take care of our children and we have already run out of the saveings my husband wanteed to go back to his job. He was informed that his collegue holds his positona and due to the crisis theycan not sign another contract with him.

What ca we do in this situation?