Can anyone answer me please

After being trying for 2 years ,we want to do

IUI

! My husband has sperm issues , low motility, but he had good count 226 million , 7% morphology this numbers where in March .In that time we found out that he has thyroid level very high .We went to fertility clinic to do

IUI

but the doct suggests us to finish his treatment with thyroid medication first and than we can do the

IUI

. So his thyroid level come back Normal after 2 months, fertility doct told him to check semen analysis again, and I couldn’t believe it and still I can’t believe it he has now count 60 mil , motility 26% morphology 1% . Is only three months apart and this dramatically change, how is that possible? Why ?! We have done everything good , vitamins, no smoking, no drinking. I told them to repeat because doesn’t make sense to me, but the doct said to check again in the end of August. The analysis in March was done in another fertility office, my hubby is been there 3-4 time and the numbers were almost same except motility every time that he did the test. Was his first time in this clinic that numbers come up very bad. Sorry for being so long but I really need your opinions or experiences.My first questions is can we still do

IUI

with this numbers? CAn thyroid medication make his numbers worst . Just give me any hope and any suggestions please 🙏