Ms. Marhue also advises families to agree on sharing the work of house hunting, as she felt overloaded during the two years it took to find the right property in Ottawa. “I felt like it was my responsibility to find something that fit everybody else. The burden should fall on everybody,” she said. Instead, “everybody kept rejecting what I found.”

And if aging parents are planning on leaving the family home, it is time to start purging now. “We had to push back on that,” said Christa Battaglia, 39, a director of communications at Northwestern University who lives in a duplex in the Andersonville area of Chicago with her husband, Brendan Keating, their children and her 83-year-old father. “There’s my dad’s old stuff, his old papers from college. I said, ‘We don’t really need that anymore.’ He’s like, ‘Well, it’s interesting.’”

Jessica Peterson, 37, who works in talent acquisition for an insurance company, said that when she moved her parents from Virginia to Monroe, Conn. — where she had found a two-family home they could share, so she could help with her ailing father — even a 40-foot U-Haul truck plus another 20-foot truck was not sufficient to transport all their belongings.

Ms. Peterson now wishes she had tapped her parents’ network to help with the move. “Don’t be afraid to ask for help, but have really specific jobs, like one person to pack the kitchen,” she said.

On the Hunt

Once you have decided where you will be looking for a home, it is important to find a broker who knows the area well and is familiar with the multifamily market there. Bear in mind that if the older generation is moving from a longtime family home to a completely new community, their concerns should be carefully weighed when considering what type of home to buy.

Some house hunters described the in-law suites in homes they saw as “an afterthought” and “mom lives like a troll in the basement,” which is why Ms. Peterson’s family would start with the in-law suite during showings. “We knew that if that didn’t fit with what my mom and dad were looking for, it didn’t matter if the rest of the house was beautiful,” she said.

Finding an agent who has experience with multigenerational arrangements can help smooth the process. Karen K.H. Park, for example, specializes in selling multimillion-dollar homes to Chinese and Korean families in the Fort Lee, N.J., area. Ms. Park, who is Korean-American, said she can commiserate with Asian parents whose children have brought them to the country. “I understand their culture,” she said. Also, “Korean is my mother tongue. I can fully support the family.”