tha'ts the worst, i'm sorry. nothing like a new plant falling apart. i love plants, and i grow them by instinct, i dont know that much about them. in my experience jade's are a very hardy plant, you can grow a new one from a healthy leaf in a new pot. i would also try not watering it for awhile, jades can survive with minimal water, they store it in their leaves. i would bet that a jade would outlast any bugs with no water coming in.

im sorry your plant is having trouble, i hope it has a speedy recovery!