1, be patient. There used to be a man next door who took him home for a long time in the summer vacation. Seriously, you must be patient.

2, the requirements should not be too high, and the requirements for him should be low. Don't expect him to pay three or five times, you must take your time;

3, mainly games, in fact, most children need this, spend more time with him and take him to play games;

In fact, to sum up, it is no different from educating other children, but it needs more patience and time. Take your time and educate them like ordinary children. Take your time. Don't always think about his mental retardation and want to give up. In other words, if he is mentally retarded, he is obviously 10 years old, but he looks like a 3-year-old child. Then teach him as a 3-year-old, and hope you can succeed.