Is there such a thing as a senior custody battle? For instance if a son wants to put parent in a SNF, but the senior's sibling does not?

So, he is doing ok at the care home. I have tried to back away as much as possible, but am increasingly irritated by his family. Since thay have NOT been very involved up to now, they keep turning to me for answers, and it really bothers me that they are so awkward at communication. Tyler still does not seem to want to deal directly with me, so he has the girl text me questions. I do not like her at all, but I was raised to be polite. I suppose part of it is my deeply ingrained Baptist upbringing, it seems appalling to me that they have been together ten years, have 3 small children together, and still have not wed. Shame on me I guess for believing in morals....
I have given them all passwords, account information, dates due, and still she has questions.Tonight it was about medications. Supposedly two are nowhere to be found. He has a grey lunchbox type bag that he keeps all his meds in. If the bottles are not in it then I have no idea where else they would be. My first thought was that the two bottles may have fallen out in one or another of the vehicles, ambulance, etc that he has been in over the past two weeks. I do not want to even suggest they ask the autistic son...