ANSWER:
If the parents want, they can divide their assets among their children equally and give them as gifts, however this should be done for real, on papers and they should give the ownership to the children, it shouldn’t be just on documents nor that they will get the possession after the parents death. They can’t give one child “his share” in order to be deprived of it after they die. This is not valid.
But the children have no right in forcing the parents to do this while they’re still alive.