Is confining an adult son to a separate room—due to his health and aggressive behavioral condition—considered a sin upon the parents?

There is no harm in detaining a son to prevent him from harming himself or others. The Sharia came to remove harm, as the Prophet, peace and blessings be upon him, said: "There shall be no harm or reciprocating harm." The jurists have stipulated the permissibility of shackling an insane person with iron if there is fear for him or from him. They also mentioned that the guardian of the insane person is obligated to manage his affairs and care for them in a way that achieves his benefit, and to restrain him and keep him from harming people or being harmed by them, as a protection for him and a preservation for society.