My husband has hit his head a few times pretty hard over the last couple years. he no longer has a sense of smell. no he does not have covid. this is something going on for some time. is it related possibly, the loss of smell?

I cannot put episodes of simple head trauma as the cause of a loss of the sense of smell. Some people lose it for no apparent reason. He may have had an otherwise symptom free process that attacked the nerve endings like covid does and never knew it.

Common head injuries experienced by most of us will not damage the olfactory nerve, but facial trauma sufficient to fracture facial bones can damage the cribriform plate and cause loss of smell. An occult virus can also cause loss of smell. An otolaryngologist would be the best consult, especially to evaluate the sinuses and upper airways.