Truth is its so often hard to tell. All you can do, is offer friendship and if that gets used in some way against you or disrespected, then walk away knowing you did right with head high. In the long run it's their loss, and bone or tusks don't show up on weekends to help you shift house, or share a beer.
Ive had similar happen to what you describe, and it sucks! But then It makes me think about my real mates and appreciate them and the things they do more.
Just recently I had to think about pulling out of a big hunting trip due to a few factors like step daughter heading off to University making spare money tight. I told the guys I couldn't go, and got told, "nah, you're coming, I got this."
In the end I didn't need the help, but I will never forget the offer!
My experience is, it will work out the best for you Terry, and the worst for them as the good people drop away and they are only left surrounded by others like them.