...when you show up at your old family doctor's office, and instead of getting "I remember when you were this-high!", you get pulled aside to discuss your parents condition and geriatric evaluations.
...when you feel like a parent to your parents, because you have to guide, direct, and counsel them.
...when you are excited to see the Meals on Wheels van that comes for your folks, because you don't feel like cooking since you have been busy with medical powers of attorney, calling doctors, and checking and cross checking finances.
...when you pay odd bills for your parents (like fines for blowing through EZ Pass on the Parkway) because it is just easier than explaining it.