Unsolicited advice is almost never the best way to really help someone you care about in our experience.
It makes them mad and usually secretly want to punch you in the face.
They don’t really care or listen to your unsolicited advice.
It leads to a disconnection between the two of you.
and often it has the opposite effect of what you intended because the rebellious part of them rears it’s ugly head and says “no I won’t do that just because you said I should.”
In our experience it’s better to avoid giving the unsolicited advice if you really want to help them and ask a few good questions, especially surrounding the consequences of their choices, to hopefully give them some more mental wiggle room to possibly make a change in the future.
(this is in a personal context – not when someone is paying you for your advice or has explicitly asked for it.)