I agree that a text can help provide context, and I definitely prefer it for non-emergency communications, but sometimes people want to go straight to synchronous communication so they can discuss urgent details without delay.
> The text message should explain the nature of the call and which number to call in reply.
You lost me here. If I get an unsolicited text message claiming to be a doctor who needs to speak to me urgently about a loved one's medical emergency, I'm not calling back via any number other than the hospital's front desk or switchboard. Invoking an emergency and asking you to call an unverified phone number is scamming 101.
> The text message should explain the nature of the call and which number to call in reply.
You lost me here. If I get an unsolicited text message claiming to be a doctor who needs to speak to me urgently about a loved one's medical emergency, I'm not calling back via any number other than the hospital's front desk or switchboard. Invoking an emergency and asking you to call an unverified phone number is scamming 101.