Is it permissible to separate a father from his son?
General Chapter
Al-Mughni
Book of Jihad
Primary text
Separation between a father and his son is impermissible according to the Hanafi school and a view within the Shafi'i school. The evidence cited is that the father is one of the two parents, akin to the mother. This ruling applies regardless of whether the child is major or minor, based on the general scope of the prohibitive report, and because the adult son is still harmed by separation from his father, demonstrated by the requirement of their permission for Jihad.
Supporting text
Some Shafi'i scholars and Malik permit this separation, arguing the father is not inherently entitled to custody and there is no explicit text forbidding it, unlike the case of the mother who is more compassionate. There is a second narration from Imam Ahmad restricting the prohibition of separation to young children.