"I was flying by the seat of my pants," says Baldocchi, an employment specialist in San Francisco. Both of her parents are 83, and she knew her father couldn't handle her mother's care.

The hospital recommended putting her mother in a nursing home. Baldocchi wasn't willing to do that. But moving her back into her parents' home created other problems.

Baldocchi, 48, is married and lives about a mile away from her parents. She has a full-time job and has back problems that make it difficult for her to lift her mother. "I couldn't do it all," she says. "But I didn't even know how to find help."

With help from the Family Caregiver Alliance, she eventually hired a live-in caregiver. "But even if you plan intellectually and legally, you're never ready for the emotional impact," Baldocchi says. In the first two months after her mother's stroke, she lost about 30 pounds as stress mounted.

More than 42 million Americans provide family caregiving for an adult who needs help with daily activities, according to a 2009 survey by the AARP. An additional 61.6 million provided at least some care during the year.

And many are unprepared.

Starting with the paperwork

While many parents lack an advance care directive, it's the most basic and important step they can take. The directive includes several parts, including: a durable power of attorney, which gives someone legal authority to make financial decisions on another's behalf; a health care proxy is similar to the power of attorney, except it allows someone to make decisions regarding medical treatment; and a living will outlines instructions for end-of-life care. (For example, parents can say if they want to be kept alive by artificial measures.)

"It's invaluable for the kids, because it's hard to make those decisions for a parent," says Jennifer Cona, an elder-law attorney at Genser Dubow Genser & Cona in Melville, N.Y.

An advance care directive is the first line of defense if a situation arises, says Kathleen Kelly, executive director of the Family Caregiver Alliance, which supports and educates caregivers.

Without an advance directive, the family will have to petition the court to be appointed the parent's legal guardian, says AgingCare.com.

It's important for families to talk about long-term care so the adult children know their parents' preferences, wishes and goals, says Lynn Feinberg, a caregiving expert at AARP. But it's not an easy conversation.

Elderly parents are sometimes suspicious of their children's financial motives, says Susan John, a financial planner at Financial Focus in Wolfeboro, N.H. One client asked John to hold a family meeting because they needed an intermediary to talk about financial issues, she says.

And when there are many siblings, the family decisions can become a three-ring circus with much acrimony, says Ann-Margaret Carrozza, an elder-law attorney in Glen Cove, N.Y.

Families who need information and help sorting out disagreements can call on elder-law attorneys, financial planners, geriatric care managers, and caregiver support groups. In February, AARP said it will offer its members a new caregiving support service through financial services firm Genworth.

Navigating the long-term care system

Many families are unprepared for quick decisions, especially when they find out that Medicare doesn't pay for long-term care, Feinberg says.

The median cost of a year in a private room at a nursing home in 2011 was $77,745, according to Genworth. And only those who have spent most of their assets can qualify for Medicaid to pay for the nursing home.

Assisted living is another option. Residents can have their own apartment to maintain some independence. But the facilities generally provide personal care services, such as meals, housekeeping and assistance with activities.

Still, it's not cheap: The national median cost in 2011 was $39,135, according to Genworth. Assisted living isn't covered by Medicaid.

If they have a choice, at least 90% of elderly parents prefer to stay at home as long as they can, according to AARP research.

But if the parents can no longer safely live at home, it can be hard for children to move them into an adult care facility.

There may be another option. Sometimes the home can be modified so a parent can stay there. For example, Baldocchi put in a chair lift for her mother. She also arranged for a home caregiver.

The job of family caregivers

Family caregivers take over many responsibilities. One might manage a parent's finances, while another sibling will take the parent to doctors' appointments and shopping. Those who move in with a parent take on a significant and sustained burden of care.

Jan Walker moved into her mother's home in Leesburg, Fla. After her mother, who is 83, had fallen, she wasn't able to get around as well.

Walker, 55, has three brothers. But she is the only daughter, is divorced and has no children. "I always knew that this was the role that I would have, and I guess my mind was prepared for it," says Walker, who now is a full-time caregiver and works from home as a tutorial instructor for a digital scrapbooking website.

"When you get into the trenches, it's literally baptism by fire," she says. "New things come up. It's not just about advance planning for finances or medical care. It's everything," she says.

Caregivers need to also watch their own health. "There is such a thing as caregiver burnout," Cona says. Among female caregivers 50 and older, 20% reported symptoms of depression, according to a 2010 study on working caregivers by MetLife.

"It's a hard job," Walker says. "But most worthwhile things are hard. She was always there for me when I needed a helping hand. It's only natural that I be here for her now."