This is an absolutely vital book for anyone with a loved one dealing with anosognosia - the inability to tell you're mentally ill, which can look like denial. The basics of this book are summed up by Dr. Amador's acronym: LEAP.
L is for listen.
E is for empathize.
A is for agree.
P is for partner.
If you've had tough conflict with the individual previously over their illness, the first hidden step is to actually apologize - even if you've done nothing wrong. This is a key point throughout the LEAP method: apologize and empathize with what they're feeling, even if you've done nothing wrong or they're not in reality.
The first named part of LEAP is listen. Dr. Amador goes into detail about how to actively listen. All of this is simply good advice, regardless of if someone is mentally ill or just in a heightened emotional state.
Empathizing is the next part. Even if you disagree with someone's entire version of reality, empathize with the way they're feeling from it. This is simply the kind, loving thing to do. Maybe you're 100% certain the things they're seeing/remembering aren't real, but the suffering these things cause your loved one is 100% real, regardless of the reality of the cause.
After that, find agreements. Instead of focusing on where you disagree (whether treatment is needed), focus on what you both see. It could be you both agree their sleep is bad and would like that to improve or that both of you would like them to be able to work. Find and focus on the common ground.
With that common ground, partner on making those things happen. That way, it's not you being pro-pills vs them being anti-pills. It's both of you collaborating on how to help them achieve a goal you agree with.
Another key component of the LEAP method that doesn't exactly fit in the framework, but is implied by the L being primary is to NOT give you opinion until asked. And then, even after that, apologize for what you're about to say because you know they're not going to like it. Personally, I'm a bit of a chronic "fixer" (always giving unsolicited advice and jumping into problem solving). I should heed this advice throughout my entire life in all of my relationships, I imagine.
Overall it's a bit poorly written and not my style of nonfiction or guidebook, but I don't think there's anything better for helping you manage a loved one with anosognosia, a common symptom of mental illnesses such as schizophrenia, schizoaffective disorder, bipolar, dementia, and so on.