Clingy baby help

I'm watching my friends baby and she will be 1 on October 16th. My friend says she sleeps in her crib and doesn't get coddled at home, they let the baby cry it out, but at my house I can't get her to sleep in the crib, the play pen nothing she crys and crys and the only way I can get her to sleep is if she is cuddled up in a blanket on my lap...her mother swears up and down to let her cry it out and she will eventually fall please!