I certainly understand why you are confused. androgen insensitivity is a term that is used for two totally separate problems. One is very common and appears to be what you're very normally genetic husband, with normal fertility
has-low production of testosterone
which is completely treatable by testosterone replacement for which he is undergoing any supervised .
The other androgen insensitivity disorder is when a genetically normal male, XY, does not have receptors for testosterone and so develops as a phenotypically (meaning the appearance of) normal female. A person with congenital androgen insensitivity disorder looks like a normal woman. Obviously your husband does not have a congenital androgen insensitivity. It has no implications for your sons and the surgery for the undescended testicle was merely a coincidence and also a common condition that does not necessarily affect his future fertility. They are all normal guys. I hope this clears up the confusion. It is nice to send some good news.