Pregnant after birth

I have heard that you are most fertile after giving birth. My best friend just had a baby 5 weeks ago. They do not want to have another for a couple years!! Yet she told me they've had unprotected sex 5 times now and he finishes inside her (she got the okay to have sex already from her ob). I told her to be careful if she doesn't want to get pregnant right away. She keeps saying it won't happen, we don't like condoms, I hate the pill la de da.

She's been having a hard time adjusting to motherhood. Baby does nothing but cry all day and night, her husband works 12 hours a day, she's not working and feels alone. I'm so afraid of her getting pregnant right now bc she's so stressed out but there's nothing I can do or say.

Sorry just needed to vent.