When a man have sicklecell trait do that mean all his children will have the trait too?

Not necessarily: While it could happen, a man with trait has a 50% chance of passing the trait gene in any pregnancy. He could also pass the non-trait normal gene.Every pregnancy could have trait or normal outcome.

No: Sickle cell trait means that one is a "carrier" of the sickle cell gene. It takes two copies of the sickle cell gene to manifest sickle cell disease. If a man has sickle cell trait, he may pass the sickle cell gene or the normal gene to his offspring - meaning 50% risk that he will pass on the sickle cell gene. The offspring's chance of inheritance also depends on the status of the mother!