When a moderator has a personal relationship with the user, should you allow another moderator to take action?
Almost always. In fact, ask another moderator to take care of it. Business + friends almost always == disaster.
Some things that could go wrong:
- You might not give them enough punishment/be lenient on them.
- They could accuse you of giving them too much of a punishment and say, "I'm nice to you, why do you have to be a jerk?"
- Another member of the community might say that you didn't punish them enough (even if you did).
- It could make other moderators cautions or skeptical, making this entire thing a bigger deal than it needs to be.
I don't see any real advantage to doing this. Just, please, don't do this.