too young or at the right age

I have a friend who has just given birth less than a month. She has always been very conscious with everything surrounding her. From her being first time pregnant till giving birth. She hears no one but except to experiement or research on almost everything. Recently when i visited her and her less than a month baby, i came to realize that there are many things which normal post pregnancy mum does which she dont practise because based on her research. But when concern me most is when she told us that she is teaching her baby to self soothe and will try her best no to co-sleep with the baby. it came to a shock because at such a young age, less than a month old, the baby was make to train to self soothe. We find it shocking as we too have a child. We understand her plight of having to care for the baby alone while her husband works. but to self soothe such a young infants, we fear she is facing a post natal blues. We have too read online that we can self soothe baby but at a recommended age of 4-6 months..We, as friends who are also mother, felt that all her baby needs now is just that warmth of a mom before he felt asleep, some fresh air, as she confine the baby in the room only, probably some playing moment. She wouldnt let anyone carry her baby when he is crying and will often try her best to "train" him to sleep even though he seems wide awake and just need a little conversation moment. does anyone practice self soothing your child as early as newborn? is my friend showing sign of post natal blues? i need advise and assurance that she is fine and she is not harming herself and baby.