Look for specific, dated incidents rather than a general impression: a missed medication week, an unreported fall, the stove left on, or a house that has become unsafe rather than merely untidy. Rule out reversible causes first -- a urinary tract infection, medication interaction, or untreated hearing loss can all mimic decline.
How families here handle this
Write down what you have actually observed, with dates, rather than relying on a vague sense that something is wrong -- specifics are what actually help a doctor, a care manager, or eventually a facility understand the real situation. It is worth testing a middle option before deciding on a permanent move: a few hours a week of in-home care, or adult day services, often buys real time to plan properly rather than deciding everything under pressure. This is rarely one dramatic moment; it is usually an accumulation that becomes undeniable to one family member well before the rest of the family sees it.