Your husband need to visit Main Immigration office in Gharrafa and meet Mr. Nasir Athiya. He should go early and by 6am he should be in main immigration. It might be hard to meet Mr. Nasir as he is busy but he is a good man and often approves. We had the same issue, we went few times there, eventually met Mr. Nasir and got his approval. I must say its very tough these days for some nationalities to get visa in Qatar, even visit visa but try try again, nothing we as public can do about it except keep trying.