Nazly, your sleep issues.
Earlier you said "he goes from sleepy land to awake land in one second and the next second he is on the go... standing up in his cot trying to climb out!" - we have had exactly this same issue since DD has been standing and cruising about.
It came about very quickly too. Going to sleep was fine one night and then she learned she was able to stand (and climb) in the cot and suddenly wouldn't stay still in the cot. Always trying to crawl around or stand, even when dog-tired.
So what has solved it for us is the shock return of the swaddle sheet. I did it in desperation at first. At 3am one night when DD had spent over 90 minutes shuffling around in her cot and not staying still, I dug out the swaddle sheet (which hasn't been used for about 4 months) and as soon as she was swaddled she settled. Literally within 15 seconds. Immediately asleep.
I thin we've been swaddling for just over a week now - naps and night time. It has soooooo worked.
But. Did you use the swaddle when younger? I read on the Lullaby Trust website (worried about swaddling risks in the older baby) that while there is no upper limit on when you should stop swaddling. It did say that a swaddle shouldn't be introduced after 3 months of age unless it was established in the first 3 months. That the risks of later swaddling is only when it is a new thing.
You know before we were talking about baby's personal preferences being different to what you expected to be doing? Well DH & I are wondering if DD will be the first of our 4 children who will not use a sleeping bag. Maybe her personal preference is showing us that she prefers the tightly tucked in blanket that keeps her still and secure.
When I remember back to my childhood, I never liked duvets and always preferred blankets and sheets on my bed. Precisely because I liked to be tucked in and you can't tuck a duvet in. I think DD is showing us that she doesn't like the looseness of the sleeping bag and prefers to feel tight and secure in order to sleep.
Sorry for the long post. Hope it helps thought.
I will also do a little plug for persisting with a dummy. They are fantastic for independent self settling to sleep. It's a little late to be establishing it, but might still be doable.