I would be concerned with the degree of influence this Amy so called Wiccan seems to have over your ex-friend while he is in a most vulnerable state. Grief can make dealing with everyday decisions difficult let alone the more complicated ones that are part of losing a spouse. Things that can have huge financial consequences if badly done. Is it possible she is encouraging his dependency and pushing him to isolate friends?
If you can reach out to any of his family members you might want to tell them what happened and see if this is happening to to them and other friends. Not saying you need to renew the friendship. Outright attacks on your faith and blasphemy are pretty much a sign to shut that door.
I don’t know any of his family members and frankly it would be a little ‘stalker-ish’ to reach out to any of them anyways. He was a former police sergeant so hopefully he knows the scams.