Generally - IME - when the cause of death is unknown and occurred outside of a medical setting, tests will be run to determine the cause of death. Waiting for results or the eventual need for an autopsy won't necessarily hold up an obituary or a funeral or a burial, but it could delay a cremation. Even if they believe the deceased did not die under suspicious causes, the death certificate will require a definitive cause of death.
My good friend (& neighbor's) brother died very suddenly of meningitis. His mom tucked him into bed at age 12 with tylenol because he had 101 fever and he was dead the next morning. The police didn't leave the house until the coroner could certain that it was not likely a murder. Even though everyone - including the police - knew it was some sort of tragic illness, the PD stayed on the scene and greeted everyone who came by (very nicely) until they got word that they could leave. It took nearly the entire day but it was a Sunday.
In the situation you are describing, I would probably let JT's text go unanswered. I am so so sorry for your bewildered mommy heart.
