Your boss isn't Andrew Waters, the new head of the cult, is he? Is the cult still going strong after the early death of the cult founder Theun Mares? Frequently these insane science fiction cults go away after the founders death.
As far as the YMCA, I've known people fairly high up the management ladder and if a grooming sex-offender creepy "satanic" cultist were made public by a civil suit/letters to the highest person in the org you can find to address them to, that person would be gone.
While no longer a staunch Christian org, this sort of thing would be dealt with internally and quickly.
I would think about reporting this man to the YMCA and to the authorities (since minors are being groomed as well, according to you.)
Not Andrew Waters, i don't know if the cult is going strong or not. The person who groomed me was a long distance apprentice of Theuns so i never interacted directly with the group.
I am hoping that the person will get fired immediately once bring this public in the next month or two with a suit but maybe it would be best to start with a letter to a big wig in the YMCA.
I've reported him to the police because i did see him grooming a 15 year old(according to me).