I read online, in books and saw bunch of videos saying that a baby after a certain age (3 months I think) is able to sleep a whole night or for a few good hours. It's confusing because you hear that and on another side you hear that you should feed your baby and it's normal to wake up at night.

I made up my mind that I will wake up for him and just let it fix itself, but deep down I want to sleep
Also I heard from a relative and a neighbor (they both fed their baby at night and woke up a lot), that it continued till 2.5 years! that's a lot, considering that my baby is 7 months old, it's a log way to go.
Yes, I think the studies suggest that after 6 weeks babies no longer need a feed overnight ( I was told this also). But I have yet to meet anyone who didn't need to feed their baby of this young age overnight. 6 weeks is highly unrealistic. Some babies just need to be fed more frequently than others. I stopped overnight feeds at around 5 months and this was only because I chose to settle my dd when she woke at 4am rather than feed her. I had success because in less than 5 minutes she was fast asleep again (we use a dummy so this helped a lot!) But had she been difficult to settle without a feed I would have continued to feed until she was ready. Just trust what your instincts are telling you