[@thewizardguy] A Chryssalid actually only requires a nervous system and will likely absorb nutrients. But you're right they wouldn't have a long term utility. 

They could also just imbue him with Bambietta's Reishi and have his entire body disintegrate if he turns on them. Like everything in his body turns into a bomb. No need to mind control him, because that seems impossible. Especially if he's willing to deal.