Well said. This is what I was expecting to see but everyone was so ready, lmao.
Asking the daughter is a fair idea, but she's clearly in serious distress and we don't exactly have time to explain enough for her consent to really be informed. This isn't a hospital room, it's a first responder situation.
The thornier issue is what that position means in the aftermath.
Real medicine has a practical cutoff, past a certain point dead is just dead. Presumably everyone killed here is in the same boat as this guy though, which means they can theoretically be brought back. If we accept that this is life saving medicine then withholding it without extremely good cause is unethical*. Following that to its natural conclusion it'd be hypocritical to prevent him from doing this later if he can, turning this into the proper birth of a new court as a faction instead of a proof of concept.
Given how special the circumstances are here I wouldn't be surprised if these guys are notably stronger than the base charm suggests they should be. Similar to how Olivia got lots of benefits converting over her mortal exp and traits from her background.
This guy is the first Day Caste of the new era, and this will be the first significant action he takes with that power, He's probably the first one to use this particular charm in any age too since Kindred aren't a thing in this setting. That doesn't smell like a recipe for entry level 15th gens to me.
* The only practical good causes I can see for this are the triage and first responder rules. A doctor has to use their resources in a way that helps as many people as possible, and that can often mean picking who gets help in time to survive.
First responders are also trained not to provide help if doing so would make them a casualty. So not immediately spending all essence on this while in a war zone would generally conform to the spirit of the ethical guidelines even if the result is that some people are permanently lost for whatever reason.