as far as I know people´s dreams are what they saw somewhere in the past, or somethingg like this, so I would like to know what can blind men dream?
Depends how long they’ve been blind.
Someone who became blind later in life would likely still dream in images, although they would likely fade over time. Those who have been blind for life typically dream in sounds/touch.
Previous threads discussing this in GQ:
What do blind people dream?
Can blind people “see” in their dreams?