Please help me find a joke. It's about people with mental retardation.

Said a silly boy got married and his father-in-law wanted to visit his house. His father didn't want to see his in-laws, so he made an excuse to go out.

He was afraid that his son would be looked down upon by his in-laws, so he taught his son a few words:

If someone asks: Where did your father go? Just say: Go up the hill and play chess with the old monk. Go back early when you get up, and sleep late, old monk.

Ask your mother, you will say: go to grandma's house to see grandma.

Ask your donkey and you will say: Well, that old beast is eating grass in the backyard.

After my father left, my father-in-law really came.

Grandfather looked at the yard. Why is there no one? Immediately ask: (His father-in-law didn't ask him in his father's order)

Grandfather: Where's your mother?

Silly little: Go up the mountain and play chess with the old monk. Go back early if you get on, and don't go back if you are late. You will sleep with the old monk.

Grandpa: Where's your donkey?

Silly little: I went to grandma's house to see grandma.

Grandfather: Where's your father?

Silly: Well, that old beast is eating grass in the backyard.