His dr said to use a humidifier just want to make sure. is it safe to use vicks humidifier with 1 month old?

Humdifier: If you put the Vicks in the humidifier and not on the baby, it is ok.

Humdifiers: If you live in a dry climate a humidifier is a good idea for nasal congestion and dry skin. Adding Vicks will not be harmful. I would suggest you try nasal saline drops if your infant is congested. Use 5-6 drops in one nostril and then wait and use it in the other. The congestion will clear and this can be used as often as your infant needs it.