Complex sentence: Their statement addresses a belief that someone has permanent and absolute power over another's drinking, but it does not answer the idea that someone could provide "any" measure of help or support toward someone else's sobriety or treatment of someone else's addiction.
Split into simpler sentences: Their statement addresses a belief that someone has permanent and total power or control over another's drinking. However, it does not answer the idea that someone could provide "any" measure of help or support toward someone else's sobriety or treatment of someone else's addiction.