Do you know what supplements were being used by the previous owner and how often for each? Was the chameleon getting exposure to the UVB light?
If it really does have MBD that wasn't treated then it needs extra calcium until the bones are strong again and then it needs appropriate supplements, exposure to UVB light, appropriate temperatures and the insects need a proper diet to stop the MBD from returning.
The extra calcium should be in the form of liquid calcium sandoz or gluconate because they absorb better.
The supplements schedule should be phosphorous - free calcium at most feedings to help make up for the usually poor ratio of calcium to phosphorous found in most feeder insects.
Phosphorus -free calcium D3 powder twice a month and a vitamin powder that contains a beta carotene (prOformed) source of vitamin A twice a month. PrOformed sources of vitamin A cannot build up in the system like prEformed sources can and will not lead to overdoses. This leaves it up to you to decide whether the chameleon needs prEformed vitamin A or not.
Appropriate temperatures allow for proper digestion and thus indirectly in nutrient absorption.
Exposure to the UVB allows the chameleon to produce the D3 it needs to use the calcium in its system. D3 produced from exposure to UVB won't likely build up in the system and lead to overdoses like too much D3 from supplements can.
Feeding/gutloading the insects ensures your chameleon gets a healthy diet. Insects such as crickets, superworms, roaches, locusts canned be fed greens such as collards, escarole, endive, dandelion greens, kale, etc and veggies such as carrots, sweet red pepper, squash, zucchini, sweet potato, etc.
Still would separate them. Some stress is not noticeable until it's too late.
