My Godson comes to me regularly for advice, to vent, to confide in, and just to feel out ideas and thoughts he's having about his life, his relationship, pretty much everything. The fact that he comes to me drives my sister absolutely insane, but I wouldn't think of turning him away. I love him.
Because of my estranged relationship with his mother, loco sister, I was very cautious when my Godson would come to me. I would do a lot of listening. I would validate most of his emotions and only if he asked for them, I would give him my thoughts. Our relationship has evolved and grown a lot over the past 3-4 years. He's a difficult child, in case I didn't mention that.
He told me that the reason he comes to me is because I LISTEN and when I offer him advice, I speak to him as a peer, not as a younger person. He says he feels respected; that even if I disagree with his choices, I don't make him feel stupid. BUt most of all, he feels comforted by the fact that I keep everything we talk about under wraps and private.
I also ask a lot of questions to get a better idea of just what's going on with him on that particular day or that particular moment. My Godson is a confused young man and a little immature - I think he is really struggling with being an adult and figuring our what's expected of him. Rather than telling him what he needs to do, we just kind of talk until he comes to it on his own. Usually it works out, other times he flubs up.
There have been times when I've been worried about his safety and said so - but with love and compassion being key elements in my statements.
Also, the tone of voice is very important, in my opinion. His parents speak to him as a parent to a child. My nephew is 26 years of age. I speak to him as another adult and he once stated that he likes that. My feeling is that even adults make stupid mistakes and need guidance along the way...even me at 45 years of age. I try to keep my voice calm and my responses as neutral as possible. I am flattered that he thinks so much of me to confide his most personal thoughts in me.
So, my thoughts are that what constitutes good advice is to first be a good listener. Learn and understand what motivates the person your friend wants to give advice to. Be compassionate and realize that there is no "one size fits all" to how we each live our lives. Offering advice and telling someone what they 'should' do are two different things and your friend needs to temper his need to impress upon his Godson what he 'should do' with what his Godson may need from him overall.
That said, I have to say that there have been times when I don't think easy child, difficult child or my Godson or anyone else is really hearing my words of wisdom (hah!) and then later they can repeat something I've said verbatum! So, I think they are always listening, they just need to find the right time to use what you've said to them in their own sweet time!