Sweethearts since high school, my friend Mitzi and her husband, Jack, a retired dentist, have been married 55 years. They've raised two children, who honored them with three grandkids.

In retirement, Mitzi became a painter while Jack enrolled in college classes for credit, studied hard and aced the finals. Jack led adult education classes at his synagogue and played a brooding Hamlet during a weekend of play-reading in the mountains.

However, in the past year, my husband and I have observed Jack crumble. His conversation has centered on his search for a pain doctor to cope with severe sciatica. He arrived at a play with a special pillow and popped a handful of pills before the first act. Even with pain meds, he struggled to stand up at intermission.

Jack limped, a sideways crabwalk. One evening, as we all started to leave their home, Mitzi confided, "Jack is becoming confused." Then she turned to Jack with a sharp reminder, "Take along your medication." We climbed into their car and Mitzi directed Jack to make every turn, so he wouldn't forget the way to our destination.

"She won't leave me alone," Jack told me in a low voice, tossing a despairing look in the direction of his capable wife, who walked ahead to manage our restaurant reservations.

About that time, their son's job as accountant for a large hotel chain evaporated because of the economic slump. Despite valiant efforts, Robert was unable to find another position secure enough to support his wife and two girls. His wife went to work, but the family's position was precarious.

Jack stepped in, and together he and his son became licensed insurance brokers specializing in medical malpractice insurance. Jack's background in medicine put him in a leadership position.

The next theater date, Jack met us with a sparkle in his eye and spring in his step, the limp lost in enthusiasm. "These days my recreational reading is actuarial tables and regulations," he said, laughing. "Robert and I opened an office. The doctors are stacked up, waiting to talk to us."

Mitzi "took a back seat," looking on as Jack held the floor. Jack's love of learning was only surpassed by his love for his son. Jack's goal was to set up a business that would give Robert a secure future. Working 10 hours a day, learning a new profession, building momentum with his son agreed with Jack. Mitzi helped out at the office if they needed her.

I've read that in societies where people live longest, the "seniors" build houses for the new generation and consult on future community plans.

Robert's misfortune molded Jack's reemergence as a problem solver for his family. His resurgence of good health blossomed spontaneously. Sense of purpose and vitality don't just belong to the young. Jack demonstrated that necessity can have rejuvenation as its partner.

And finally, a word about using skills gained from years of experience. Yes, studying art history captivated Jack, but rediscovering a need for his professional expertise became the best medicine for his body and for his soul.

Newport Beach resident CARRIE LUGER SLAYBACK is a retired teacher who ran the Los Angeles Marathon at age 70, winning first place in her age group. Her blog is lazyracer@blogspot.com.