@GnomeDePlume Please don't doubt yourself, because you are someone who always gives good, supportive advice on this thread.
Yes, you show compassion.
I'm sure that nobody here thinks anything bad of you, truly.
Of course you're conflicted about your mother. Not everyone has a good relationship with their parents, for many, many reasons.
You've said in the past that your brother's raison d'être is his relationship with your mother. He has clearly realised that she is his anchor, and that he is about to be cast adrift.
He also seems to have a skewed idea that the administration of morphine will hasten your mother's death. It won't - it will just ease her passing.
He's terrified of her death and feels that he can't agree to anything which might (in his eyes) make it happen any faster. He doesn't trust the CH staff and feels that he has to gatekeep everything that they do to your mother. It wouldn't surprise me if he thought that they dislike her enough to just give her morphine so that she's less trouble to them.
Gnome, in my opinion, this is just your brother trying to orchestrate things and exert a degree of control, on your mother's behalf. You've spent many years seeing through him. Your reaction is to be expected.