The first thing i'd do, is to take your live glider to the vet. Make sure he is healthy. I know how you feel but you have to stay calm. After you take him to the vet, get tests done and (hopefully) he is healthy, you can worry about getting a cagemate. If your current baby is healthy he wont drop dead, he will be lonely though. Spend as much time with him as possible. When he's sleeping in his pouch you can stick your hand in and let him cuddle it. When you are ready, you can find gliders on facebook buy and sell for exotics, craigslist, breeders in your area or online. I'm sorry for your loss.