One needs to be very careful about offering advice.

Everyone has his/her life chart - things that he/she needs to learn
here on Earth.   Any unsolicited (unasked for) advice is a negative
intrusion into the person's life chart, no matter how well-intended
and loving the offered advice was.
The result of that is that a part of what was going on, which the
unsolicited advice pertained to, can rub off onto the person who was
giving the advice.   In other words, the person who was giving the
unsolicited advice not only has his/her own lessons to learn and
things to go through, now he/she also has taken on some extra
baggage from the other person.   That could be too much for the
advice-offerer and he/she could get bogged down by the extra baggage
and even eventually collapse!

So what to do when you think someone could use some advice?
Nothing.   The person is working out his/her issues and if he/she
doesn't ask for advice, then he/she doesn't want one.
At the most one could ask " may I help you? "   Unless the answer
is a resolute " yes " , the advice shouldn't be offered.
If that person answers " with what? " or " how? " then the best way
is to ask again " how would you like I to help? "   If that person
still doesn't answer specifically how, it's the best to walk away.

Of course, if the person asks for a piece of advice, it's OK to give it,
as long as it pertains to what was asked.   One shouldn't assume
anything.   As long as you help with what was asked for, you are
safe: nothing will " rub off " onto you.