Is a son considered disobedient to his father if he disobeys his command regarding prohibiting him from hosting friends in his private apartment, knowing that the father stipulated that hosting friends should be in his (the father's) house, and knowing also that these friends are diligent in prayer and congregational prayer and have memorized parts of the Qur’an?

The child must obey his father in this matter, because it is not an act of disobedience. Hosting friends is commendable (mustahabb), but obeying the father is obligatory (wajib). The obligatory takes precedence over the commendable. Most often, a father does not prevent his son from something unless it is for his own benefit. If the child sees no justification for the prevention, let him try to convince his father without disobeying him.