Hello Jack, I'm sorry to hear of your father's situation. And whatever happened to bedside manner.

Would the following phrasing work for you? Feel free to edit it to your own needs. I will put it up temporarily in this form for now,
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May Jack H's father John, whose aortic dissection is considered inoperable and likely fatal by his current doctors, be healed, and make a physical recovery to the full extent that providence allows, and be able to enjoy more time together with his loved ones.