all your life your going to meet people who drag you down and
give you nothing but grief. i see it like theres two things to do

1] you can realize that this person is dependant on you and you can manipulate them into doing things for your benefit [if your smart]

2] learn to shake em off and remove them from your life.
out of sight is out of mind .the sooner you snap on your buddy
the better. be straight up and tell him exactly how you feel.
when your done talking he should feel like crap so maybe he will change