Hi 16yrs. I am so sorry for all the pain you are experiencing. You have already received more wisdom from the folks here than I have to offer. I can only say that I relate to what you say here because I have also been afraid for what my son might do to others. If he is 18+ then HE is responsible for his actions not you. I have to keep telling myself that so I don't take on what is not mine.
We love, nurture and protect our children never imagining feeling that we may need to protect others from THEM. The kids are no longer shaking the chain bridge on the playground so you do not need to run to the rescue. The idea of a meeting or a written communication with those who may be impacted sounds like a good way to warn people of the hurricane possibly coming but not taking on the responsibility of it. Other than what you may need to do as an employer keeping the workplace safe, do only what gives you peace.
Perhaps you can spend some energy taking care of yourself. Sounds like a lot of loss has come your way. It is not selfish to focus your energy on recovering. I only have three kids and I struggled meeting all the demands. You are caring for four and running a family business. My bones are creaking just thinking of your to do list!
Of course at my most exhausted, I would bristle when people suggested I take care of myself because I honestly had no idea how to do that. My body rebelled and I started getting migraines and had a full on exhaustion collapse. This episode forced me to learn that I had to give myself permission to NOT take care of everything or fix everything. I didn't believe anyone could fill in for me until my body went on strike and I was down for two weeks. Others could and did step in. I guess we all have to find our own way but just know that you deserve a break and the chance to hold back some of your energy for yourself. Ironically, it is the most caring thing you can do for the people you love.
Love and care to you!