It's very difficult to counsel ‘adults’ even out of the cults our nation has, and they are not near the lifetime Brainwashing and strong indoctrination techniques used in the Muslim Culture via Islamic teachings glorifying death....to unravel these is like unraveling a plate of spaghetti. ...often with one who is not exactly willingly to cooperate and sees you as an enemy....further having also been taught how to resist.
Even if with Gods help they do leave Islam.....they will loose their family members as well as their community and culture and sometimes even their life.... Then they generally face years of counseling because Islamic teachings are so deeply ingrained and brutal work to loosen their grip.
Those who become Christians also have years before they are truly free from this stronghold....it's always creeping up as is the very nature of Islam.
And yes, most Muslims have one form or another of mental illness.....you cannot live in their culture “norms” without developing these. The Western thought that by changing their surroundings you'll change them isn't true because we allow the Mosques, Teachers and Islamic Community centers to isolate them and reinforce Islamic indoctrination....and recruit our own people to them....instead of ridding these we're bringing Islamic History and teachings into our own schools and Universities in order to desensitize the public from calling it what it is...a death cult.
So you see it's going to grow as the cancer it is with precious few willing to surgically remove it......instead we're feeding it every day.
Devout Moslems should be treated as aliens from another planet. They are less than human. Killing them is doing them a favor. It is imperative, if the human race is to survive.
Trump is catching hell from CAIR, the PR wing of the American Muslims for suggesting what you have stated as the only way to get rid of the Islam scourge.