My Husband Has Head Ache Past Three Weeks, GP Thinks

my husband has head ache past three weeks, GP thinks it could be cluster headache, given him proponolol 10mg tds to take, after single dose feels mild pain in his left arm,
his pain never seems to be going down, eyes are waterry, feels heavy headed, very irritated, seen by optician and by there report no issue with eye
could some one give me what can we do for it?