If you are not sure of your husband's reaction to his results, talk to him. It might be worth it to go through the counseling sessions prior to learning his results. He is the best judge of what information he can handle at this time. You do not mention his age, but unless he is showing symptoms, I would not reveal anything to his employer. If there is a strong safety concern regarding softer cognitive symptoms, perhaps he could develop a close working relationship with a neurologist (who knows HD) or neuropsychologist. They will pick up on the earlier subtle changes which may affect his job performance.
You may feel pressed to reveal his results to identify what is happening with your son, but bear in mind, while a negative result in your husband can rule out JHD, a positive result does not confirm it until your son is also tested. There may be another issue going on. The only way to be sure it is HD is to have your son tested.
I hope your family is able to figure out what is going on and able to make some good plans to deal with it. You have reached out to the right place. There are many helpful and understanding people here.
Patty