Sure, here are the matches:

1. What’s the matter with him?
**b. He has a high fever**

2. What’s the matter with you?
**d. I have a headache**

3. You should drink warm water
**f. Yes, I will**

4. She has a stomach ache
**a. She shouldn’t eat a lot of sweets**

5. What’s the matter with your mother?
**h. She has a backache**

6. I have a bad toothache
**c. Oh, poor you!**

7. Where’s Tim?
**e. He’s at home**

8. Where are you going now?
**g. I’m going to the dentist**

So the final matches are:

1 - b
2 - d
3 - f
4 - a
5 - h
6 - c
7 - e
8 - g