An employer is not automatically liable for losses in the workplace. Your husband will need to check his original contract of employment and/or his employment handbook to determine whether his employer is liable for the losses. The contract of employment may contain a specific clause by which his employer agrees to look after his belongings at work. This may be in the contract itself, or in the handbook or other documents which are given to staff such as the health and safety manual. Your husband will need to look at whether his employer or his colleagues have been careless. Everyone has a duty not to be negligent (careless) in ways which could lead to the loss or damage of other people's property. He needs to identify anything which could prove that his employer or colleagues have been negligent in a way which has contributed to the loss that your husband has suffered. If he can show that they are to blame in some way, then your husband may be entitled to compensation. To do this he can either deal with the matter himself by lodging a formal complaint and then taking the matter to the Small Claims court or by instructing a solicitor to make the claim for him.
I hope this assists.