The kind of issues Kimberly Weihl, 55, of Midland, Mich., is facing, for instance. When Ms. Weihl took out a loan for her daughter to attend Saginaw Valley State University in 2007, she was already paying down $60,000 of her own student debt. Now she owes $77,000. Her daughter, who dropped out after two years at Saginaw State and is living at home, is working as a waitress and not yet able to help with payments, which come to $500 a month.

Ms. Weihl cannot foresee a future in which she is able to retire from her nursing job. “I’m convinced I’m going to die before I resolve this,” she said. “I can’t sleep at night. My stomach is in knots.”

Julie B. Miller, a researcher at the M.I.T. AgeLab who is studying how college debt affects family relationships, said student loans and longevity planning are at odds within many debt-saddled households. Pre-retirement milestones like paying off a mortgage get shelved in favor of paying off loans, she said. In some cases, like Ms. Weihl’s, borrowers’ mental or physical health suffers.

“They’ll say, ‘It’s either, make my loan payment this month or do the root canal,’” Dr. Miller said. Sometimes consequences cross generations. “We’ve had borrowers say, ‘My loans are impacting my ability to help my mom, who’s in a nursing home, financially.’”

The Donohues’ debt load owes itself to four separate loans. Each daughter graduated from a California public university. The part that mystifies Mr. Donohue is how the cost of education so quickly managed to outpace his ability to pay.

“I graduated from a private college, the University of the Pacific, in 1978,” he said. “There were state scholarships available at that time, and I had a little baseball scholarship, and I came out with $3,000 in debt.” (This amounts to about $12,000 in inflation-adjusted dollars.) He was able to pay that off before he got married in 1988. Since then, he said, “the cost of college has become a nightmare and a scandal.”

His daughters do not disagree. Kelly Donohue, 31, the oldest daughter, recently paid off her portion of the family’s loans. But she still worries about her parents’ future. “The parent loan situation has definitely made me think about how I’ll support them when they’re no longer able to work. This is something I factor into my own financial planning.”