are nannies meant to live forever?

The nanny to my first sim is still alive. He was an elder when she was a young adult, and she lived to about 108 days. I befriended him and constantly invited him over to try and get the “witness death” aspiration but he just keeps going. This same nanny appeared when I requested the service for my first sims grandchild o.O

Platform: PS4

Packs: Get to Work; Dine Out; Cool Kitchen Stuff; Holiday Celebration Pack; Grim’s Ghoulish Guitar