I have a daughter with downs syndrome, she is six now, Alhamdu Lillaah, she gone through a lot of big tests; her intelligent is about 3-4 (according to doctors assessment), she has a very good memory, quick response, loving and caring, polite, etc., but she can't talk very clearly, and sometimes when I teach her about Islaam, sometimes it seems that she understand, she knows that when she go out she has to put on her Hijaab, she likes listening to Qur'aan, she knows how to pray, etc... I want to ask in my daughter's case, does she has to responsible for her doings in this world and Hereafter? Are there any teaching materials and channel that I can use to teach her about Islaam? I am afraid that I have to be questioned in the Judgment Day for how I bring-up my daughter. I love my daughter very much.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

The person is legally held responsible and accountable for his acts in the Hereafter if he is pubescent and is in sound and sane state. The Prophet said: "The pen is lifted (stopped from writing the deeds) from three: the sleeping person until he wakes up, the mentally handicapped or insane person till he becomes able to reason and the child till he grows up (reaches the age of puberty)." [Abu Daawood] So whoever is pubescent and is in sound mind becomes responsible of his acts, but whoever has not yet reached the age of puberty, is not held accountable about his acts. 

Since your daughter is only six years old, then she is not yet an adult and therefore is not held accountable. We are not aware of the disease that you are asking about and to what extent it affects the mind. However, if the person affected by it, has reached the level of being mentally handicapped to an extent that he/she is said to be mad or insane, then he/she is not held responsible. The fact that your daughter covers her hair when going out, or performs prayers is not an evidence that she knows what she is doing, as many mentally handicapped people perform prayer just because they are imitating others. But if you can train her to perform the religious requirements then this is a good thing and may Allaah put that in the record of your good deeds, and may Allaah bring your daughter up according to righteousness. As regards the educational materials for children of her age, you should ask the people who are specialized in this field. Searching other Islamic websites may help.

Allaah knows best.