can human clearly remember their dreams after few years?

Your question is too vague and too general. "All humans".  We are not all alike. You're trying to lump every single person in one slot. We are not one-size-fits-all. 

We are all different. Whether someone can remember their dreams depends on how memorable the dream was, did they write down the dream, do they have a good memory, etc.

Any significate emotionaly driven impact,

be it in the dream state or otherwise can be

stored in your memory for long periods of time,

possible for life.

Everyone isn't the same, but some people can, yes. I vividly remember the strangest dream to remember, which I had when I was 7: I found a shipwreck, walked to the other side of the ship, and a large duck popped out and attacked my leg! I woke up from the scare, lol!