New member challenged by delusions

Hi everyone - just signed up here. 72 y.o. husband has moderate dementia, not Alzheimer’s, but due to changes from acquired brain injury from adolescent-onset hydrocephalus. He has a long history of persecutory delusions - there has often been an individual in his life that he believes intends to harm him. Those mostly have not interfered with his functioning. But in the past ~year he has developed a fixed delusion that someone is tampering with his Depends, so he refuses to wear most of them. (He has neurogenic bladder and episodic bowel incontinence). He takes them out of the package, unfolds them, deems them defective "because they don't make the noise they used to make - they are changed", and then he stashes them in several places in his room. He does eventually independently get dressed in a pair of Depends, so on some level this delusion is harmless. However, I frequently have to cajole him into putting on a pair that he thinks is defective. I understand that by definition, reason does not affect delusions. But I can't buy a dozen packages of Depends, so that he can choose one or two pairs that pass muster, while discarding the rest. I know arguing is not the way to deal with this, but unfortunately I have tried to convince him that there is nothing wrong with his Depends, to no avail. I suspect he may think a perpetrator is coming into his room and tampering with his Depends. I don't think he thinks it's me, but IDK. (He and I live alone together). Anyway, this is driving me nuts, I am open to suggestions about how to handle this. Also, just this morning out of the blue, he accused me of tearing up some old letters of his. He's never mistreated me in any way, he is very loving and kind, and I am not afraid of him, but I have heard that sometimes delusional people begin to seek to harm their spouses, so I have a small general concern about my own safety. In general, at what point do delusions become the reason why caregivers place their spouses in memory care? Any and all feedback is welcome, thank you in advance for your kindness.