As to my knowledge medical certificate is not required by Qatar embassy for family visit visa, My brother has recently sponsor his wife on family visit visa for 6 months and no medical certificate was ask by Qatar Embassy in the Philippines,only here in Qatar that medical is required if you stays more than one month.

Don't try sending your visa together with your "unfit" medical to the embassy,surely it will be disapprove,they are very strict with medical...wait for another 3 months till such time your problem with your health will be cured.

Again hope it helps you...