How to calm an aggressive or violent person with hd?

Patience and Safety. Frist and foremost makes sure the patient and the others around him or her is safe. Sometimes you might need to call 911. Try to identify triggers - sometimes places, things, and even people can trigger these responses. Be patient and be attentive. Try to reduce distractions in the environment that can be overstimulating the patient medication.
You need help. You should speak to a neurologist and then to a psychopharmacologist to get help.