I am just curious if the little fish swimming around that your neighbor thinks are FHM aren't really YOY BG. So many people see little fish and think they are "minnows".
If you create habitat that is so thick to protect FHM, it will also over protect BG and other panfish. This may cause them to overpopulate and stunt as well.
FHM evolved to live in poor water quality conditions. Such as bodies of water that are shallow and prone to winter killing. They are capable of tolerating the low DO levels, however predators like bass aren't. They certainly can and will live in high water quality bodies of water, but these places can support predators and that is their demise.