Yes Drake's actual diagnosis is almost always terminal. However, I don't know how many of the cast/crew/staff knew anything other than he had "personal time off" or something vague of that nature, or a nonspecific health situation. The family kept things very private and did NOT want the details leaked at all.
I think only very few of the cast/crew/staff knew the actual diagnosis. Obviously Greg Vaughan knew, because, after Drake passed away, GV shared on his instagram texts that he had exchanged with Drake. And after Drake passed, Christopher Sean said in an interview that Drake had told him the truth privately in a dressing room. I think others said so too, in interviews.
I don't want to get into the details of which actors knew what and when, as those details and interviews were all already posted on the Drake thread.
As I said, many did NOT know, as the family didn't want it leaked.
My point is this: I don't have BTS knowledge, so I don't know when the writing team and directors knew what. Eventually they were informed, as we know that management communicated with Drake about writing in John's death. But did Ron know? Or was it not known until the new writing team came in?
This I have no idea about, no idea at all.
But yeah, if Ron did know, then the writing does seem insensitive or at least awkward.