What does it mean to compare your son to a leather jacket?

Comparing my son to a leather jacket means that my son is as warm as a leather jacket, but it also means that my son is as expensive as a leather jacket and it is difficult to give up. This metaphor means that a son, like a leather jacket, can provide protection in cold weather, but at the same time it may be as precious and irreplaceable as a leather jacket. This metaphor expresses the father's deep love and cherish for his son.