I think the extreme measure called for in extreme situations is knocking on someone’s door, offering to be with them, telling them how you feel, and listening to them. I’d never call services, or go to them for help unless I knew what they were offering something useful. Usually they aren’t. But when someone does’t answer the door, the phone or online contact and is at risk for physical medical reasons or is so distressed that they could have committed suicide already (or be in the process of committing suicide) is a real possibility I will call the police. They could be dead, in which case it needs dealing with, or they might not be in which case it might lead to them being sectioned, which while worse in most cases could lead to a constructive convesation about how to proceed when the person gets out if something similar occurs in the future. They were difficult choices.