That could be a number of substances to be fair, especially Ketamin as it’s a disassociate drug. Could be crack as it impairs reality or hullucinates. It’s hard to pinpoint just by what you say as to what substance he could be using as it’s not really enough information.
People on drugs are selfish and have little feelings for others. I know that’s harsh but that’s the truth. Addiction consumes people and sadly that’s why places like this exist because families and relationships suffer tremendously.
From experience id say protect yourself and focus on you. Nothing you do will ever change his behaviors, however if you change how you react then things might get better.
Drugs and Alcohol destroys lives. Like I said families and the addict.