I'm just starting the Essence portion. My guild is also largely burnt-out on Firelands, and I recognized early that nine other people are not near as invested in my staff as I am. And understandably so! So I actually started pulling together my own resources a few weeks ago. It's too soon to report success or failure yet, but my recommendations to your mage are these:

- Be proactive. Arrange your own raids. No-one can ninja your essences if you're the ML.
- Be patient. Saying 'Hey, we're going this day at this time, show up if you like' may get you a better response than bugging people about it whenever there's a free moment. That tank may be more inclined to go when it's optional rather than mandatory. At the very least he won't feel guilty about skipping, which should improve guild relations.
- Find a partner/sponsor. I've got a healer and a tank who've agreed to stick it out with me (one of them is a guild officer) and it makes me feel less alone. :-D It's also easier to PUG additional DPS and alts when I've got a core!
- Network. Talk to other guilds, other friends, and other friends' guilds. I've got a good relationship with another guild that's still raiding FL and has agreed to put me on their backup roster.
- Scale it back. 4/7 HM is awesome, but your staff doesn't care about progression. My 10s guild can clear 6/7 normal FL in about two hours (you don't get essences from Rag anyway), and while it might mean an extra couple weeks of raiding, they'll be more pleasant weeks if you're zipping through and having a good time instead of stressing.

I understand your worry about alt nights not working, but I will say... my entire guild was loudly done with FL until I started posting up my alt runs, and yet last two weeks I've had more signups than slots. So, I guess people weren't as burned out as they thought. ;-)

Good luck to your mage. I hope it works out for all of you!