Hey Ber
Can I ask are you from the UK? Reason being that if you are, xanax here is likely to be fake and therefore some other benzo, whereas in the US I know its prescribed.
I know from my own experience that what he is taking is a lethal combination, a quick Google search will reveal that. Additionally sportpoeder seems to be phenibut, which works a bit like alcohol I think, I haven’t a great deal of experience with this aside from taking it once a few years ago.
Anyhow, what would help is how much is he drinking and taking xanax?
The combination is dangerous, and it can also be dangerous to suddenly stop without supervision so need to be super careful with the approach here