How long for zero sperm count to change with medicine?

Bailey • Ava Madeline🧸 07/23/2020🌈 IVF baby

He went to the urologist yesterday they sent him to do genetic blood work so now we just waiting until the results come back which takes forever his next appt is January 25th but the doctor said his testicle size is normal and everything feels normal and his semen ph and fluids were all normal he just had no sperm!

So they think maybe his brain is telling his body not to make sperm or he has a blockage we will find out in January but if it is a chemical thing how long for medicine to fix and produce sperm?