NEW YORK (REUTERS) - For years, Madeleine Smithberg has been at the forefront of American comedy as co-creator of "The Daily Show" and a talent coordinator for "Late Show with David Letterman."

That sense of humor was especially handy during the last few years. That is because Smithberg had to cope with not one, but two elderly parents in rapid decline.

"It's heartbreaking," says Smithberg, 56, who heads a production company in Los Angeles. "And yet it's invisible, because nobody talks about it."

Dealing with one aging parent is challenging enough, whether you are helping navigate the complex healthcare system, paying for an assisted living facility or struggling with cognitive decline as the parent slips away. But the emotional and financial stress can be more than double if you are caring for both parents at the same time.

"It's like having toddlers," says Smithberg, whose father passed away in 2014 after she moved her parents to Los Angeles. "They're hot, they're cold, they're hungry, they ask repetitive questions, and their needs become the most important thing in the world at that second... The biggest challenge of all is holding onto your patience."

According to a new study by Northwestern Mutual, the childrearing comparison is apt: 59 percent of Americans feel that taking care of two parents between ages 85 and 90 would be even harder than handling two kids between ages 3 and 5.

Caregivers may also have kids of their own. In that case, it's not just the "Sandwich Generation"—it's a Triple-Decker.

The Northwestern Mutual report found that 38 percent of those surveyed have not planned at all for handling the financial burdens of caring for elderly parents.

The costs can be gigantic: National median costs for an assisted-living facility are now $43,200 annually, according to insurer Genworth Financial in its annual Cost of Care study. A private room in a nursing home? $91,250.

That is more than enough to blow up any financial plan. The following is advice on how to care for your parents without going bankrupt yourself.

Long-Term Care

"Long-term care, long-term care, long-term care." That's the simple advice from Smithberg. Her father had taken out coverage for himself and his wife, which she calls "the best thing he ever did."

Long-term care insurance covers expenses for nursing home or home care if you become incapacitated—most of which is not covered by Medicare. The coverage, like the care, can be extremely expensive, and to be sure, it did not cover all of Smithberg's parents' assisted-living costs. But, combined with their own life savings, the policy has meant that she has not yet had to dip into her own savings to pay for their care.

Have the Talk

With the holidays right around the corner, it is one of the few times of year when far-flung families tend to gather in one place. Don't let the opportunity slip by to discuss your parents' expectations, should illness arrive. Find out if they have advance directives—documents that spell out what treatment they would and would not want during a life-threatening health crisis. Make sure you establish who has power of attorney, should they need someone to make important decisions.

"It's the perfect time to have this kind of conversation," says Kamilah Williams-Kemp, Northwestern Mutual's vice president of long-term care. Her spouse's grandmother lived to 102, and her mother-in-law has been diagnosed with Parkinson's.