Box 14 on Form W-2 is a non-computational box. It may be used by issuers to report a variety of items such as, state disability taxes, union due, etc.
In your husband's case, since the form was issued for disability payments, I suspect it is a reference to the type of disability payment (50% of salary, perhaps?). I would suggest leaving it out of the input fields in TurboTax, as only the dollar amount of the disability payments and any taxes withheld are relevant.