I just lost my almost 2 month old baby to sepsis. im wondering what causes it? can my other children have it? how long could he have had it?

Sad for your loss: At that age it is likely baby just harbored a germ it acquired from your birth canal prior to or during delivery. That germ could hibernate for 8 or more weeks and suddenly cause fever/sepsis. Group B strep is a common such germ. This is a problem specific to the post newborn period & not known to be a risk to others. Please discuss this with your babies doc to clarify this issue.