Sick Glider - Calcium Deficiency- Diet help!

Hello Everyone, I'm new here and this is my first post in the Health issue area (And I hope it will be my last!).

Last night my male sugar glider was in a terrible state. At 1 in the morning I noticed he wasn't awake, but my female was, so I opened the nest box and it didn't appear that he was breathing. I nudged him a little roughly twice, and he woke up. He was ice cold, and very weak; Though I'm not sure if he was weak from just waking up. He walked as though he was drunk, and his left cheek was slightly swollen, his eyes sunken and his ears drooping.

He has a big habit of biting, and when he went to bite my finger he could barely put any pressure into it. Without knowing what else to do I gave him and her some raw yogurt (This has been a part of their diet for awhile, a spoonful once a week or so). I put some calcium on the yogurt and on his fruit as well. (I give them a frozen mix of peach, melon, strawberry, and Pineapple, though they rarely tough the Pineapple of strawberry.

After awhile of him sleeping on my neck under my hoody, which warmed him up significantly, he licked the calcium off of the melon and began to eat again before starting to get his "attitude" again.

So what I'm thinking happened was that he was deficient in calcium as this morning his eyes are bright, ears perky, body temperature seems regulated, he's got his crabbing sound back, and he's walking normally again.

As for my questions:

What kind of diet should I have him (and the female) on to insure this doesn't happen again? Is there a specific pellet or block formula? What about fruits vs. veggies? Are any of the fruits I'm giving them "poisonous" to them? I heard that peach isn't the best for them, but is this correct?

Is this healthy behavior perhaps a fluke? Could there be a relapse into that state again?

Thank you very much for your suggestions/hasty responses.

~Sarah