In your husband’s chart both Mercury and Jupiter are lords of Dagdha rasis. Jupiter is also a badhaka. Dasa lord is also Jupiter. In Saptamsa, Jupiter is in the 12th but with the Lagna lord Mercury. The combination receives aspect from Saturn.
Both Mercury and Jupiter are in Graha Yuddha too. Venus, in the nakshatra of Ketu is also weak. This creates problems of sperm quality and quantity. His case is a little more difficult.
Still, he can strengthen his Jupiter by wearing a Yellow Saphire on his right hand fore finger or as a pendant with a sankalpa for getting a child. The Saphire should be set in gold with back open to let the rays pass through the stone to the skin. He may visit places of Guru like Mantralaya, Saib baba mandir, Raghavendra mandir etc. and wear yellow clothes more.
Continue the doctor’s visits too.
Next year or two could prove lucky if both have done the pariharas with Sankalpa.