Very simply put:
1) Obstructing an officer is providing misleading information=guilty
2) Party to a crime is being involved in the commission of a crime and doing nothing to stop it=guilty
3) Don't expect anyone on this forum to feel sorry for you when you made us all look bad by knowingly committing these crimes.
4) If you had no knowledge of his intention to commit these crimes, I'd say he should help you pay the fine. Fact of the matter is, you knew of the impending violations and you did nothing to stop them. The fine is yours, take responsibility for your actions and pay it.