Try reading the linked blog post again, and hold up your proposed question against each of Dave Bailey’s suggestions.

Isn't that what negotiation is about, when dealing with someone who won't effectively communicate their thoughts? Speculating the wants/needs of that person and addressing them directly? This isn't something I'm making up, I've just read it in "Never Split the Difference". The book was written to address situations just like OPs.

The example sentence structure was meant to be paraphrased. I was hoping for critique on the subject matter not the grammar. I feel uncomfortable turning OP's anecdote into a hypothetical anyway so I'll back off.

That's corpo-marketing style. The angle is to coerce the other in a corner and he'll see it coming from a thousand mile and react badly to it.

> "We understand that we need you to be the man of the family,

That's exactly the problem and what OP don't want/need. They want to communicate with the medical and legal staff. They don't need him to be the man of the family, they need him to approach this as a family. They need him to let them be family and they need him to be family.

You have a theory, but even if you are a good people reader, and even if you are mostly right, you are very likely to be wrong in many small but important ways. I'm sure you can recall instances where someone was right about you in general but wrong in small ways that really mattered to you.

Even if you have a guess, ask instead.

No, negotiation is the process that happens when you and the other party have decided you want to work out a mutually acceptable agreement. The other person in this situation has not decided to do that, and so the trick is how to get the him to that point. I think Zelphyr's approach would be a lot more likely than yours to have that effect.

I'd say this part is even more difficult than the stuff in the post, and requires serious empathy.

The most powerful and influential communicators/connectors I've encountered in my life essentially only ever do this. I suppose the nuance is that they treat every person as an individual, so (on a semi-subconscious level) spend their first interactions profiling the individual so they understand their motives. I liken it to boxers learning their opponent's range and rhythm (only less combative).

I suppose what might be patronizing though is projecting thoughts onto a stranger from afar (like on this thread) though presenting some projections as an example of one possible thought pattern that may need to be handled can be useful IMO.

Directly saying "I appreciate that you have stepped up to be strong for all of us. Can we help?" seems better.

OP is the son-in-law. The man who has power of attorney over OP's father-in-law is the son. Unless I am misunderstanding your post. It would absolutely be an odd mistake to make if wrong though.