On the other hand, some members here have developed a great reputation because they post to give information and answers, ask questions because they're genuinely interested in learning, and they create friendships and business relationships..these people are the first ones on BP I'd approach on the site when looking for a partner/money/contact, etc.

Hi Dan,My financial experience is limited, so these are just general thoughts on your situation.Above all consider the value of your friendship together and make sure that’s the most protected thing in any long term financial agreement you might enter into.  

And then over time, you decide the types of people you're willing to work with, and who YOU want to reward (with your business, money, time, loyalty, partnership, friendship...). 

Get to an attorney and put this relationship in writing to protect both of you and your friendship 

It's fine to have people leave their info and reason to sell on your website, however this becomes very impersonal and off putting to some who you really need to call and build a "friendship" with before they open up.

For the friendships which we buy with a price, and do not gain by greatness and nobility of character, though they be fairly earned are not made good, but fail us when we have occasion to use them."-- Niccolò Machiavelli

It's a business, not a friendship.

You can't treat this business as a friendship.  

Do you have a lot of experience with him either in business or just in a general friendship?

I have had long discussions with large E and O companies before about their stats.In property management your friend might be okay in the beginning but if something goes wrong the owner and the tenant turn on the PM very quickly as the scapegoat.It sounds like to me this isn't worth the hassle of the small coin or something going wrong and souring a friendship.