When do you speak up when you think a friend is in the wrong?

Two things have come up in the recent past for me - probably more - but these are on my mind this morning. 

First - an old friend came over yesterday - a friend from high school, and our first few years of marriage, but I haven't seen him in years.  And by years I mean like maybe 15 of them.  Anyway - he was in town for an HS reunion that I couldn't attend, and was eager to stop by.  He started asking me about my kids and where we'd moved from/to recently - but shortly after that the conversation turned to him.  Just him. Only him. Well him and his amazingly successful family.  At one point I was getting cold sitting on our deck when the sun moved so we were in the shade - so I suggested we go for a walk.  We walked slowly for 1.25+ miles and he talked nonstop.  Finally - at the point he was leaving (2.5 hours later) he asked one question about me - well - he asked if my dad was still alive.  I was able to say "No - he died last April..." and before I could get the date out he was telling me about how ever since he was in 4th grade he was sort of psychic and knew when people had died - and the guy who designed the playground at some school somewhere, whose wife had died that he saw in a grocery store - yeah - okay - I'm done here - I don't remember the rest.  Anyway - think about that.  I had nearly told him my dad had died and his response was "oh hey that reminds me of a story about how interesting I am."

So - how do I respond? I'm so tired of people tolerating mediocrity - but I don't think it's my place to intercede here.  Should I call him and tell him he was selfish? (sounds like an attack) Was I just being selfish because he was so selfish that I couldn't be selfish enough myself? Should I call him and ask him if he's okay because I thought he was acting strangely (sounds passive aggressive) Should I just engage him in some sort of normal "I haven't seen you for 15 years" type of relationship to try to get to know him better and find out if there is something tragic going on in his life that led him to need to seek me and tell me all about himself? (I'm not sure I have room in my life for this level of involvement). Do I commit to pray for him? (That's always a good thing to do but again there are limits to prayer time). Do I just let this thing fade away until the next reunion that I don't go to?

I'm not really asking for advice here - I'm mostly just laying this out. By God's grace I'll come back and tell you what I decided to do.  For now - I can tell you that I'll be praying for him.

Second - and this one is very different - is about a friend who I believe is not only involved in, but a 'purveyor' of a pyramid scheme.  Actually I need to think on this one for a while before I write it.