1. He helped Mother wash the dishes.

Question

2. He helped Mother with the dishes.

3. He helped his brother study math.
4. He helped his brother with math.

5. He helped study math.
6. He helped with math.

7. He helped his brother study math.
8. He helped me study math.
9. He helped them study math.
---------------------------------
Are they all grammatical?
Does #5 mean either 7,8,or 9?
Is #6 grammatical?

Answer 1

#5 and #6 are vague. Who did he help? How did he help? The others are excellent.