Mentally Challenged and Disabled

Q: I have a mentally challenged brother who is 29 years old. He insists that he has to come to the musjid with us. In the musjid he is extremely disruptive and reads his qiraats and tasbeehs, etc. aloud. If he makes wudu in the musjid, he wets himself as if he had a bath as well as others around him. He reads every masnoon dua e.g. entering the musjid, leaving the musjid, dua after wudu etc. all aloud. Even his thanaa in jamaat is read aloud as well as his takbeere oola. Sometimes he makes 4 to 5 sajdas in one rakaat. He disturbs the entire congregation. However if we leave him at home he goes mad and starts screaming shouting and sometimes even becoming violent. The other day we left him and went to the musjid he ran after the car the whole way and by the time he got to the musjid he was screaming and breathing heavily and it was really embarrassing as well as disturbing to the entire musjid. We really don't know what to do!

1. Is it better for us to take him with to the musjid and disturb everyone or can we read our jamaat at home with him because it is basically impossible to go to the musjid without him due to his violent reaction if we leave him at home?

2. Since he is a maazoor, who will get the sin of him causing takleef to every person in the musjid at every namaaz?

3. Will the hukm of qisaas etc. be applied to him? For example, if he hurts someone or breaks someone's car etc. Will he be mukallaf? If not, who is responsible for his damages?

4. I read a narration in Muslim Shareef of a mentally challenged person in the time of Nabi صلي الله عليه وسلم, who was told to stand in the saff of the children? Can this be used as a proof that a mentally challenged person can go to the musjid?

5. Who is responsible after his parents for looking after him?

6. We sometimes treat him very badly and shout at him a lot because he is extremely difficult to live with and we run out of patience with him. We have all really lost sabr with him. Will we be sinful for hurting his feelings and shouting at him? Even though he refuses to listen we still shout at him and we know he can't help it, it's not his fault , but we too cannot help shouting and correcting him rudely.

7. As encouragement for us, what is the reward for living with such people?

8. What naseehat/guidance does our Deen give us in regards to living/interacting with such people?

Q: I have a seven year old son that is disabled.

Since he is incapable of seeing to his needs, his mother and I attend to him and bath him, change his diapers, wash him, change his clothing, etc.

1. We always try to attend to him in private so that his satr is not exposed to people unnecessarily. However, is it permissible for us to look at his satr while bathing him, changing his diaper, etc, to ensure that it has been cleaned adequately?

2. When performing his istinjaa and cleaning his satr area, I do so with my bare hand. Sometimes, I need to apply medication to these areas as well and do so with my bare hand. Is this permissible?

3. When he gets older, will it be impermissible for his mother to attend to these needs of his? If so, at what age will this apply?

Q: Do psychopaths and sociopaths go to Jahannam?

Q: Are the utterances of irtidad by an insane person considered. Will fasakh take place of his nikaah? What happens when the insanity is self induced. Meaning he became insane due to using drug substances. Will his utterances be considered?