Is it permissible for a mentally disabled person to marry?

It is permissible to marry off a mentally disabled person to protect them from the harm of lust, to safeguard them from immorality, and to secure care and service for them, among other permissible purposes. However, if the disabled person is insane, their guardian marries them off. But if they are rational or lucid at times, they marry themselves off. In addition to the well-known conditions for marriage, this marriage requires informing the other party about the disability, and that the disabled person be trustworthy, not known for aggression or corruption. A minor and an insane person are not permitted to directly contract a marriage due to their lack of legal capacity. The guardianship over them is a compulsory guardianship, so the guardian may marry them off without their permission if there is a benefit in it.