My boyfriend stopped drinking about a year ago after having sesures and dts. He has resently started thrashing in his sleep. Any relation?

Thrashing in sleep. There are many causes for abnormal movements in sleep, such as rem behavior disorder (normally our muscles are paralyzed when we dream, if this does not happen we can act out our dreams), a nrem arousal disorder (arousals from deep sleep with abnormal movements), or, rarely, even seizures. Sleep apnea can cause arousals with abnormal movements. Unlikely to be caused by stopping alcohol a year ago.
Question. I would ask him if he has started to drink, and consider testing for alcohol. Are there some emotional issues causing distress?