I guess the shift would have been around the time he began

promoting an energetic blend of conspiracy theories, COVID denial, and the liberal use of capital letters, with videos like “The TRUTH About Pfizer” and “The CDC Are SPYING On You,"

promoting ivermectin for viral infections, and hanging out with Tucker Carlson.

https://www.vice.com/en/article/z34zd9/russell-brand-ivermectin https://deadline.com/2023/07/tucker-carlson-fox-firing-reaction-russell-brand-interview-1235431938/