Good to know your kids were neutered. Did you initiate the neuters of your boys?
We had an 8 m.o. Flemish die in neuter surgery in December. He was from a backyard breeder and he was in tough shape when the woman wanting to rehome him purchased him and his bro. The boys were spraying, mounting, and marking beyond words. Rehoming person put her FGs on baking soda odor-control bedding, and they had a guinea-pig sized housing unit as their cage. Pre-surgery CBC/BMP was done prior to neuters. His bro survived. Our sweet rescue boy died at the end of his surgery; I requested a necropsy. He had less than 1/4th normal lung tissue. The odor-control baking soda bedding was probably ingested as their tiny water bottle dripped onto the bedding. (Odor-control) Baking soda per internet articles verify fatalities. | We've had approx. 45 buns spayed or neutered at our DVM, perhaps more when I check the records.
A three-four month old (captured) stray was recently neutered by our DVM clinic. He did fine. His testicles dropped, and the vet said it was time. With surgeries, there is risk, but not a reason to absolutely not proceed.