WHEN I WAS A TEEN-AGER in the '40s, one of my friends kept house for her father and young sister while she nursed her mother through terminal cancer. The strain and grief must have been enormous, yet none of her friends could help her share it. We were supposed not to know about the cancer; in those days people whispered the word as though it was obscene. Only when my friend's mother died -- that restored propriety -- were we free to say that we were sorry. I am sorry now, that when it mattered I couldn't speak.

Today people do speak about cancer. Straight talk in the media, from professionals and among friends helps to sustain patients and their families. In this open climate it is no surprise to find three new novels for young people in which a child has to deal with a parent's cancer. For children in similar situations, and for those who only wonder how you bear them, the facts -- and especially the feelings -- in these books will be reassuring. The characters aren't hoble or heroic, but they learn to support each other by sharing what they feel.

The most unlikely comforter is a girl named Lou in Judy Frank Merian's Two Ways About It, who spends each summer with her cousin Annie, the story's 11-year-old narrator. This Lou is 14, knowledgeable, foul-mouthed and mean -- the kind of kid who'd tell you were adopted and have a quick answer for every reason you could think of to prove her wrong. ("Yeah, I know, they're honest about most things. That's why I'm surprised they haven't told you.") Lou is also inventive, vulnerable and touchingly devoted to Annie's parents, so different from her own. She hides her envy of Annie beneath a flip, brash tone, while Annie can barely hide her envy of Lou's maturity and the attention her parents pay to her. The sisterly tension between the girls, heigthened when Annie's mother is hospitalized for a mastectomy,and their dependence on each other, which neither would admit to, are beautifully developed, as is Lou's award womanliness. Though an author's note acknowledges medical advice, the facts about mastectomy are somewhat skimped. Still, Annie's worst fears ("Will she just have a hole there?") are spoken and answered straightforwardly. In the end, the book is less about cancer than about many sorts of love. It is a poignant and memorable first novel.

A Season In-Between, by Jan Greenberg, is about a family that has trouble communicating. Carrie, the 12-year-old narrator, is edgy about friendships and boys and being one of only two Jewish girls at her privte school. Her father is a successful factory owner; her mother is cool, undemonstrative and something of a social climber. There's an 8-year-old brother and a brusque but kindly maid.

"I can't stand it when people talk to me about it," Carrie anguishes, after her father gets cancer. "Why is it that someone's sympathy can make you feel so terrible?" Her fear and denial, the awkward embarrassment of friends, Dad's gallant gestures toward his family before he dies, and Carrie's efforts to give and accept comfort all ring true. A curiously stiff writing style, some overdrawn characters and a pat ending with a radio obligingly playing "Turn! Turn! Turn!" ("To everything there is a season . . .") detract from this concientious portrait of an adolescent's grief.

Ronnie Schotter's A Matter of Time begins with 16-year-old Lisl at her mother's grave, then pulls back to the day when the cancer that kills her was diagnosed.

The author takes Lisl through a carefully mapped sequence of reactions, from disbelief and sorrow to denial, anger, understanding and acceptance. Along the way, as Lisl realizes that her strong, artistic mother was also insecure and lonely, her jealousy fades, and her faith in her own competence grows. The stages of the mother's illness, through her death, are described straightforwardly. Unfortunately, some of Lisl's speeches are maudlin ("I hope you can hear me, Mama . . . I wanted to tell you . . . one last time . . . I love you . . ."), her prize-winning essay is full of cliches and her talks with a smugly with-it young social worker seem contrived. Still, Lisl's story will inform, and perhaps move, young readers. Like the experience of characters in all these books, it is better for being shared.