Can you take the dummy out once he's dropped off, so he's not constantly sucking? If you can pop it in as soon as he stirs, he might drop off again.

As for helping with self settling, I started with patting to sleep (through his nappy). As he got sleepier, I'd slow the pats. Slowly weaned off that to patting the mattress, slowing that down. Or one nappy pat, one mattress pat. The pats would get further away on the mattress too. At the same time I'd do long shhhhh's, then wean off the pats and just do the shhhhing. Then I'd move away a step, until eventually it was just a few shhh's and standing at the door. Long term, I could settle, then walk away, or stand at the door a minute or two (which is what we do now, at just over three). But DS still had a dummy to get to sleep until he was 2 1/2 (I'd remove it once he was asleep) and his blankie (he has two, which are his best buddies, even now!).

HTH