My dad is 88 yrs old. He has been suffering with nonallergic rhinitis. He recently just had a allergy test, and isn t allergic to anything. He has been prescribed Zyrtec, Claritan, and different nasal sprays. He has also, had a scan of his sinuses, which was fine. Any suggestions on how he could get some relief would be appreciated. He has been to 2 ENT Drs and an Allergist.