i don't think he is alive,as for the changing back thing ,it s not true since we saw a lot of fights were the arrancar were beaten (when they invaded karukara town)and they died in the same release form ,see this page:
Bleach 206 page 04 | One Mangahe died in the released form.btw this page is not a spoiler since the same scene is in episode 119 of the anime ,but i couldn't put the anime picture