Sometimes it’s as easy as understanding what to expect. baby sleep patterns change as they grow. This is one of the main reasons it is difficult for new parents to get a newborn baby ‘under control’ with sleeping. It’s a moving target.
However, it doesn’t have to be super-hard and getting help earlier on can definitely help the family get back to the new ‘normal’ (what is normal again?!).
To get you started, just purchase the Baby Biological Sleep Window E-Book. It will answer some of your questions just like that