Have a sister who I went through similar to that woman in 1987 (minus drug addiction). Couldn’t commit her because she was an adult, police could do NOTHING until she actually DID hurt someone (threats were there)....removed her from my Mom’s house....it was NOT fun....she went on to have 2 babies, who are now functioning adults....so far ok....but, I still keep my distance....
“....threats were there...”
If somebody makes a threat, isn’t that considered assault (battery is the actual physical event) and isn’t assault a reportable crime?