Hello & welcome to Just Answer! If you have any questions after reading my answer, be sure to let me know.
I understand the anxiety of a first time father :)
From what you have described (& this is second hand information) it would appear that if the baby is sleeping peacefully, there is probably no reason to rush to the ER at the present point of time
If the child becomes excessively irritable or has repeated vomiting, or any other problem like seizures etc. then a visit to the ER is mandated
Ok great... relaying that to my friend now...
but not at the present point of time :)
Do leave a positive feedback too !
I will thanks!