I think this is best answered if the different job roles are separated out. A therapist is not the same as a social worker.
For instance, in the UK, if a report is made to Social Services about a safeguarding issue, the Social Services will investigate the case. This could be about an adult or a child. It may be that you overheard likely domestic violence in the next door apartment. It may be that you saw bruises on your friend’s child. In that case, a social worker would intervene without being asked by the individual themself. This is quite tricky, as it’s not often that people are grateful to get a call from a social worker investigating a safeguarding alert. And there is a lot of scope for an intervention to not help (famous cases include Victoria Climbie and Baby P - though there are success stories too, where a child is saved from an abusive home, these are not generally reported in the media).
I manage a service which we call floating support; it’s quite similar to the assertive community treatment model. Basically we have a team of support workers whose aim is to maintain tenancies and independent living for vulnerable people. They aren’t mental health professionals or social workers, but they have a lot of expertise in the field - they develop a support plan and help people clear rent arrears, liaise with debt agencies, get back into work, rebuild family relationships etc. We take referrals from social workers, housing officers, neighbours, friends, anyone really, including a self referral. We then contact the person to offer our service. Sometimes, they tell us to F off. Sometimes, they engage with us and we get some amazing work done.
For a social worker to make an intervention, it’s different to a service being offered. We don’t have the same statutory obligations. (Though we do have to report safeguarding alerts to Social Services).
A therapist, in my opinion, is a whole different ball game. (I’m also a therapist). That relationship is not one that flourishes unless the client has chosen in some way to be there. In floating support, we’ll signpost people to therapy, and find them cost effective options (we are particularly interested in getting people registered with a GP if they aren’t already, and in the UK you can get six NHS therapy sessions at most GP surgeries) but for a therapeutic relationship to be meaningful, the therapist shouldn’t make first contact.
Interestingly, though floating support works with people in the community, there are assertive outreach teams who attempt to engage entrenched rough sleepers to facilitate change. And that help isn’t always welcomed(though again there are success stories!!). But that is another story.