I understand your feeling about not wanting your mom to send a message to Dan. However, give your mom some credit, she cares about you and she was not born yesterday. She does have a bit more life experience than you and may look at things differently. If you watch the Fireproof movie, you will see that Caleb (the main character) has similar feelings about his mother getting involved.
If you do watch Fireproof, I would recommend you watch it by yourself and with lots of tissues handy. Ideally, it would be the best thing he could see now besides getting life advice from the Pastor. I think Dan might relate quite a bit to the Caleb character.
Mishka is correct - it is a very powerful and emotional movie for those of us who have experienced marriage problems.