It wouldn’t surprise me. While my Grandma had alzheimers, my Grandpa resolved to make sure he outlived her so she wouldn’t have to go through every day finding out her husband was dead.
At her funeral, Grandpa was in a very good mood. He gave off a Mission Accomplished vibe. He passed 30 days later.
otoh - everyone assumed my great grandmother (late 60s) would pass soon after my ggf- she had been completely dependent on him - never learned to drive, never written a check, never had a job, etc
She did/learned all of those things and more
Passed away just shy of her 90th