made his transition

[tzfujimino]

[...] One night all of his vital signs began to drop dramatically, and the head nurse, who believed in the hospice concept that no one should die alone, began to call the family members to the hospital. Then she remembered the day Bopsy had spent as a firefighter, so she called the fire chief and asked if it would be possible to send a firefighter in uniform to the hospital to be with Bopsy as he made his transition. [...]

(Source: Part of the passage named "Bopsy" in an English textbook for Japanese high school students)

What does made his transition mean in this context?

 

[tzfujimino]

Does the 'as' in that sentence mean this (#6 "used for saying that something happens at the same time as something else")?

 

[Tdol]

Yes- it means when/while.

It's one of the many euphemisms for dying.

And one of the worst in my book.