The new baby has come home and suddenly the older sibling doesn’t get the same attention as before. The newcomer is ever more demanding of their mother, whose energy may not yet have returned.

The older brother’s demands increase, too. It’s almost as if he must test to be sure that his mother will recover and that she can still care for him.

Teasing and testing, refusing bedtime and waking up each time the baby does — all are to be expected.

Sometimes an older child will take on the helping role of “big brother” or “big sister,” but don’t be fooled. Along with pride in helping, and his discovery that he is more “grown-up,” he’ll still resent the baby and feel sad about losing you.

You can make it clear that there are times when he can help, and times when he can be a baby, too.

He’s telling you, “Why did you need her? I can do anything she can. I can still be your baby and please you.” He is facing one of life’s crises and learning how to cope with it in the safety of your loving care.

Expect the older child to lose ground again at some point. Usually it’s in the developmental area he’s just mastered.

If he has begun speaking, he may resort to baby talk. If he’s feeding himself, sleeping through the night, becoming toilet-trained or conquering fears of strangers — count on a slide backward.

This is what we call a touchpoint, a temporary falling apart that anticipates a new step ahead. He is learning how to be a big brother.

Think what it means to the older child when a 2-month-old baby fusses every afternoon and parents rush to attend to her. You can help him understand his feelings. He’s working so hard to understand the new baby, and to imitate her.

“Of course you want to talk like the baby: Everyone pays so much attention to her right now.” Or, “Don’t worry about wetting the bed. Once you get used to having a baby sister, it’ll stop.”

Your understanding will be far more effective than getting annoyed or pressuring him to be a “big boy.” These responses are bound to backfire into even more dramatic bids for you to let him be your baby again.

Some children seem to sail through these first months. They are compliant, even helpful. But this interlude won’t last. The price of such a challenging new role for a child may have to be paid at a later touchpoint, or in reaction to one of the baby’s own touchpoints.

Each of his steps backward is an opportunity for you and the child to learn together to master the next stage of development.

An older sibling who is 5 or 6 years old may not express his resentment and frustration through tantrums or meltdowns; instead, he may devise ways to attract your attention by spilling things, falling or needing your help with homework. Or he may come to your side as if to help, only to drag around and get sassy with you.

But he needs the same understanding as a younger child. He will be better able to tell you how he feels than his sibling, and more able to help in a useful way once he feels understood.

Questions or comments should be addressed to Dr. T. Berry Brazelton and Dr. Joshua Sparrow, care of The New York Times Syndicate, 620 Eighth Ave., 5th Floor, New York, N.Y. 10018. Questions may also be sent by e-mail to: nytsyn-families@nytimes.com