When you have an elderly parent, going home for the holidays can be traumatic.

Geriatric social workers, financial planners and staff at long-term-care facilities have seen the same scenario play out many times: Adult children are struck by dramatic changes in their parents’ abilities to care for themselves and their home—or they realize just how quickly Mom or Dad’s memory has declined.

John Nickle

At that point, families swing into crisis mode. But with little or no time to research their options, they often are limited by what’s immediately available, says Tara Fleming-Caruso, an admissions counselor at NewBridge on the Charles, a retirement community in Dedham, Mass.

That’s what happened to Tim Prosch, a Chicago marketing consultant, on a visit to his parents, who lived in Montague, Mich. Soon after his arrival, he realized his father’s multiple sclerosis and his mother’s Alzheimer’s disease were progressing much faster than his parents had let on.

He had to scurry to get care set up for his parents in their home—and deal with his father’s trading in a PT Cruiser for a Cadillac he couldn’t afford.

Afterwards, Mr. Prosch wrote a book to goad his fellow baby boomers into making specific plans that they share with their children now, well in advance of any health crisis.

Other experts are urging families to have conversations long before any crises as well. Here are the most important topics to discuss.

Making a plan. Mr. Prosch urges couples to spend time in their 60s talking to their adult children about the size of their retirement savings, their preferences for living arrangements, long-term care and burial, and the point at which they would be OK giving up the car keys.

Those end-of-life issues are so awkward that he titled his book “The Other Talk,” hearkening back to the discussion many parents have with their children about sex.

A big part of his message: “You need to commit to full financial disclosure,” he says, adding that an audience of 50 murmured in protest when he told them that earlier this month. “It’s a cruel joke on your kids if you don’t do that. You need to prepare them for the day when they have to take control.”

To that end, he suggests putting all of the documents your children need in one binder, including your will, insurance policies and contact information, doctors you’re dealing with, diagnosis, a safe-deposit box inventory, funeral plans and the location of all of your financial assets and accounts.

After being injured on a sailboat in Italy several years ago—an accident that required 50 stitches—Mr. Prosch, now 65 years old, and his wife Pam put a binder together for their daughter, Dakota, 35.

Her parents “went through everything in their house that they considered valuable and had it appraised and took a picture of it,” she says. “They included all of their finances and a monthly budget. It’s a relief to have.”

Avoiding a crisis. For boomers caring for elderly parents, Hebrew SeniorLife, a Boston-area elder-care provider that runs NewBridge and other retirement communities, has put together a book titled “You & Your Aging Parents: A Family Approach to Lifelong Health, Wellness & Care,” downloadable at no charge atagingredefined.org.

Ms. Fleming-Caruso, who wrote a chapter about housing options in the book, says talking about a parent’s health outlook and wishes in advance can help families make more informed decisions about their care down the road.

For example, she recently worked with a woman who had helped her mother, after being diagnosed with dementia, move to an assisted-living facility.

But when her mother was hospitalized for another illness, the woman moved her to an assisted-living facility again, rather than taking more time to get her situated in a facility that could offer more care as the disease worsens.

“The daughter pulled her mom out of the hospital in the middle of several medication changes, which is a terrible way to transition an elder,” especially when the facility doesn’t offer round-the-clock care, says Ms. Fleming-Caruso.

She also encourages adult children to have conversations with their parents about their end-of-life wishes. Some strategies: You might go out to eat together or enlist an objective third party, such as a minister, social worker, geriatric-care manager or friend.

One of her colleagues, a social worker, had such talks with her father for years. When he suffered a stroke and was put on life support, “she knew instantly this was not what Dad wanted, because they had talked about this over and over again,” Ms. Fleming-Caruso says. “She was able to give him what he needed and say goodbye with a sense of peace.”

The woman’s sister, who hadn’t conducted such talks with their father, struggled with “unresolved issues” over his death, Ms. Fleming-Caruso says.

Fighting fraud. Financial exploitation costs older adults an estimated $2.9 billion a year in the U.S., according to the MetLife Mature Market Institute. The Eldercare Locator, an online directory (eldercare.gov) and call center ( 800-677-1116) supported by the federal government and run by the National Association of Area Agencies on Aging, is urging families to spend some time together over the holidays to talk and learn about ways to prevent financial exploitation.

Signs to look out for include inconsistent financial activity, confusion about recent financial arrangements, changes to key documents or an older adult’s feeling uneasy about someone seeking control of their finances.

The Eldercare Locator, with help from the National Center on Elder Abuse, has put together a free consumer guide, “Protect Your Pocketbook: Tips to Avoid Financial Exploitation” (available at www.n4a.org) to help get the conversation started.

Write to Kelly Greene at familyvalue@wsj.com