Do these sentences make sense?
1. Ask her questions about herself and her family.
2. Ask questions of her about herself and her family.
3. Ask questions of her.
4. Ask questions about herself and her family.
5. Ask questions of herself and her family.
6. Ask him the reason of problem.
7. Ask the reason of problem of him.
8. Ask the reason of him.
Comments
1,2,3,and 4 all make sense.
5 - you can't ask questions "of herself", only of her, or about herself.
6,7 and 8 don't make sense.
You could say -
Ask him to explain the problem.
or
Ask him to explain the reason for the problem.
1 and 6 makes sense