When Dr. David Klein's mother first developed Alzheimer's in 1989, he tried to write off her incidents of forgetfulness as singular events.

"Gradually, I realized it was a stage of life," the author of "Saying Good-bye: You and Your Aging Parents" said in a recent phone interview from his Michigan office.

Though the 51-year-old East Lansing physician primarily works with youths in his private practice, his mother's disease led Klein to write about adult children's experiences with aging parents, including his own.

Klein's mother died in 1992.

"You have to shift your thinking from that of a child…to being an adult caregiver. You have to give up the illusion that you have unconditional support from your parents forever. Once you enter this phase you realize that you're next in line. There's a lot of resistance to that internal shift," he says.

Growing up in the Bronx, Klein attended an Orthodox shul that instilled the values that influence his work today. Today, he's a member of a Conservative synagogue.

"The values are something that permeate almost anything I do. It's a commandment to honor your mother and father. I believe it doesn't mean to just simply treat them with respect, but to help your aging parent thrive and maintain the highest quality of life they can. It would not occur to me not to help my parents."

When parents get older, he says, it is not only their children who must adjust roles. "It's difficult for you as an adult child to imagine what it must be like for them, having been an independent, functioning person who took care of you. Now they have to accept the fact that they need help."

In "Saying Good-bye," Klein tells stories, including that of Diane, a 74-year-old widow who resisted help from her two children. Her daughter, Ellen, noticed that her mother's coat was worn and bought her a new one. Diane was insulted that her daughter didn't think she was capable of buying her own coat. Ellen, in turn, felt rejected.

In a meeting with Klein, Ellen and her brother worked out a strategy to help their mother without making her feel dependent. The next time Ellen tried to give her mother a coat, she used a different approach:

"Mom, I know you have a perfectly good coat, but there was a sale, and I got this coat at an unbelievable price. I bought it for myself, but it's too small. Maybe it will fit you. I can't return it, and I'd rather give it to you than to some stranger."

Klein says, "You have to phrase things in a way that doesn't make them feel like you're transgressing their role directly."

Even profoundly difficult parents can become easier to deal with when adult children understand their needs, Klein says.

To illustrate this in "Saying Good-bye," he tells the story of Norman, a 74-year-old stroke victim in an extended-care facility who acted so belligerently that he alienated his family and staff.

"Once staff began to see that how difficult that must be, being stuck in a body that didn't function…he became a human being and not some obnoxious person that was trying to make their life difficult," Klein says.

"He couldn't get his needs out until somebody tried to understand what he was trying to do. Once that happened he became more cooperative."

Even with the healthy elderly, Klein says, we need to pay attention to what they're really saying.

"If you say, `Let's go to dinner,' and they say, `Nah,' do they really not want to go to dinner or do they not want to spend your money?"

The dramatic life changes involved in aging are often greeted initially with defensiveness. It's a mistake, Klein says, not to pursue the issue.

"It's an initial reaction. The reality is you're introducing an idea and you're letting the person react and you should let that person go on with the discussion. It becomes a process rather than a single event. You have to anticipate defensive reactions."