This is a fine way to do things. How long the milk is frozen doesn’t really change how it should be thawed. Refrigerate over night or placing the bag in a pot of warm water is fine. After thawing, be sure to use it within 24 hours. Click here for more on how to store and thaw breastmilk.
“Is it OK to defrost frozen breast milk from a deep freezer overnight in the refrigerator and then re-heat per guidelines?”