I co-slept with DS on and off until he started sleeping all night. He is 21mo and only starting sleeping through regularly a couple of months ago. He had been doing it on and off for about 6 months, with weeks where he slept well and weeks where he was in with us every night.
All I can suggest is that you keep doing what you are comfortable with in terms of how you encourage DS to sleep better and what you can cope with in terms of lack of sleep.
I couldn't ever do any CIO/controlled crying- not because I think it's a terrible thing to do, just because it wasn't right for us and our situation. I felt like I was being a bit soft at times, and that I couldn't complain about being knackered because DS's sleep problems were ALL MY FAULT.
So we just kept trying to get him to fall asleep in his cot rather than in my arms, or settle him back in his cot at night rather than bring him in to our bed, etc. etc. but if he got really upset or we were too tired to deal with it, we just followed the path of least resistance.
Eventually, it has paid off. He sleeps well now and bedtime is lovely. I stopped bf a couple of weeks ago so he has regressed a bit (wants to fall asleep in my arms rather than in the cot) but that's fine. We have stories then cuddle until he's alseep. In a couple of weeks we'll go back to him drifting off in his cot, eventually I won't even have to be in the room when he falls asleep!
Just keep giving DS the opportunity to 'move forward' with his sleep and he will get there, slowly but surely. If you reach the point where you can't cope with his waking or settling down habits then you can do some sleep training. 6mo is teeny tiny though, so if you're happy just keep doing what you're doing. Forget about what anyone else and their babies are doing, they are all so different.
And that is the sum total of my advice! Hope it is of some use.