Is it permissible to own a trained dog for the protection, rehabilitation, and calming of individuals with autism spectrum disorder or other disabilities who require such assistance?

The Sunnah condemns keeping dogs except when necessary, as the Prophet, peace and blessings be upon him, said: "Whoever keeps a dog, except a dog for herding, hunting, or farming, will have a qirat deducted from his reward each day." Some scholars have explicitly stated the permissibility of keeping dogs for guarding homes and paths, by analogy with the cases exempted in the Hadith, due to necessity. Some have permitted keeping dogs for all benefits and for warding off harm, mentioning that the dislike applies when they are kept for no benefit or necessity. Jurists have agreed that it is not permissible to keep a dog except out of necessity, such as for hunting or guarding. Ibn al-Mibrad al-Hanbali indicated the permissibility of keeping a dog for any predominant benefit, such as protecting crops, fighting enemies, or protection from thieves. In summary: What is prohibited is keeping a dog merely for amusement and play. However, keeping it out of necessity or for a recognized benefit—such as protecting, rehabilitating, and calming individuals with autism, if this is scientifically and practically proven—is permissible.