When Alison says The Wizard of Oz (1939) the Captain says "Dorothy." The term "friends of Dorothy" was a euphemism for gay men, most often attributed to originating from the character played by gay icon Judy Garland.
Given that this season was produced in 2020/2021, Julian's contention of 27 years and 3 months of sobriety sets his year of death in 1993.