You can view all GRO death entries in England and Wales from 1837 to near enough the present year. If you live in England or Wales find your local records office and search the year in question for the surname of interest.
Does your husbands maternal grandmother remember the Christian name? Once this information is found you can then purchase the death certificate for more information, although if he died in the workhouse his details may be quite skant.
Another avenue would be to find out who paid for the funeral ~ Parish by the sounds of it, if in the workhouse. You may be able to find out which cemetery was the most likely place for your ancestor to be buried, also contact the archives to see what documentation they hold on workhouse inmates, most areas only have the account books but those books sometimes give excellent information. Some (quite rare though) have personal records of inmates, you will have to contact the archives in that region though to find out what they hold.
Really your 1st port of call is to chat to your husbands maternal Grandmother to see if she can recall the man's 1st name.