Q. How can we help our two grandchildren?

Their family was severed by divorce 18 months ago because their father was involved in adulterous relations. And this was after a trial separation, a private renewal of their marriage vows (before a minister), and counseling for several different periods during their stormy marriage.

Our daughter has custody of the children -- a boy, 12, and a girl, 8 -- but their father is very much involved in their lives, since he has them every other weekend, attends their school functions and sees that his son gets to ball practice.

Money is, of course, one of my daughter's greatest concerns. Her husband is bankrupt -- although he does pay their rent -- and she is harried. She teaches summer and winter sessions in the public schools, arranges after-school care, attends three PTA meetings a month and lives "to make it through, just one day at a time."

Our deepest concern, however, is for the son in the family who sees his father as his role model and his champion. He has heard why his mother ended the marriage, but he seems to have buried that information, or he ignores it, as we all do when it causes grief.

We don't want to remind him of this history but how can we vindicate our daughter's actions to this dear boy? He blames the divorce on his mother and constantly talks to her about "letting Daddy come back home."

It could be his age, but he has gotten listless and seems defeated so much of the time, although he makes A's and takes part in many school activities.

A. Puberty is pretty tiring in itself but your grandson's fatigue and listlessness is more than that. You're almost surely seeing a child who's depressed, and who has thrown himself into the work and play of school so he won't think as much about the divorce. He may even be trying to get his parents back together again, which isn't as far-fetched as it sounds.

The cause of the divorce may be very clear to you, and very clearly explained, but a 12-year-old is still egocentric enough to think that it's really his fault. Maybe he didn't study hard enough, or he wasn't good enough in sports or he was a smart aleck or didn't help much around the house. The guiltier he feels, the more he'll try to be good, and the more he'll try to blame the divorce on someone else.

Divorce is unimaginably hard on children, an epic sea of change that plays out their greatest fear: abandonment.

No matter how firmly the parents stand by them, the decision is still made without their approval or understanding, and they are shaken. When the center doesn't hold, nothing seems safe.

Your grandson has a terrible need to right his world now, to cling to the idea that his mom might "let Daddy come back home." It's the dream held by most children of divorce, for all children are very loyal to the family, and divorce tears their sense of loyalty apart. They think they somehow have to take sides -- to betray one parent to the other.

Your grandson may be reacting even more if his dad is intentionally pulling some heartstrings, or he may be trying to protect his father, because he knows that the weaker parent needs help the most.

While you don't want to explain the reason for the divorce -- that's not your business -- you do need to go to your daughter's defense. Remind the boy that his mom feels bad too, but she had to do what seemed best for her and the children.

You have to give credit to his father too, for he surely deserves it. Even though his repeated infidelities made marriage impossible, he follows through as a parent -- taking the children twice a month, going to their school activities and getting the boy to ball practice. This attention is just what they need.

Unless the situation is unsafe or unsound, they should spend considerable time with him, not just to strengthen their connection, but to see him, and accept him, as he is, and not as a romantic ideal.

There is another benefit. If you praise his strengths, your grandson won't have to go to his defense so much, and he won't feel quite so torn and depressed.

It may also help you to let your own anger go. This man's infidelity has hurt your daughter, his children and you, but we are all crippled in some way, and this was his handicap. Your compassion will sweeten the waters of the family well, and help your daughter make it through her days with a somewhat lighter heart.

She also needs some therapy so she can work through her anger quicker, and her daughter -- like most children of divorce -- probably needs some too. Counseling is essential for her son, however. If his depression keeps weighing him down, he'll start to think less of himself, and choose new friends who reflect this poor image -- a good way to get into trouble.

Look for a multi-age support group of young people whose parents are going through a separation or divorce. This increasingly popular choice of therapy, often found at school, or at a church, a county mental health clinic or a United Way agency, is very effective. Once your grandson talks with others in the same situation, he'll realize they are making it, and so can he.