Just because someone wants to buy your house it doesn't mean you have to sell your house. Kudos to the dude for wanting to buy property at a young age and house-hack with his roommate plan but he seems a bit….entitled. Either look elsewhere or as another poster said, purchase one of the houses that is actually for sale.
I have an 80-something neighbor who lives alone in the house she and her husband bought new in 1976, just before Prop. 13 came into effect. She's outlived her husband, is quite content in her home. Even with her health problems, a caregiver comes in a few times a week, and meals are delivered. It's actually more cost effective for some to age-in-place than move to assisted living. Unless someone's house is unaffordable or dangerous, why should they move because someone wants them to?