There are a lot of potential sources of interference but no others are mentioned. The consultant even says that the ham radio operators setup "could" cause a problem, not "is" the problem. While not obligated to do so, it might be in the ham's best interested to offer his station up for field testing with one of the insulin pumps (not connected to the user, of course) as well as RF field tests around the neighborhood. Since he is down now, it wouldn't harm him much and would be a good faith gesture. Nothing may become of the offer and it is likely that his station would be absolved of causing problems but the offer alone may go a long way toward preventing a knee-jerk reaction by the homeowners association.