The appropriateness of a grown child using the term "daddy" to refer to their father can be subjective and vary based on cultural norms, family dynamics, and personal preferences. Some families maintain this affectionate term throughout their lives, while others may transition to more mature terms like "dad" or "father" as the child grows older.
In many cultures, using "daddy" as an adult can be seen as endearing and a reflection of a close and loving relationship between the child and their father. It might be a way to maintain a sense of emotional closeness and connection.
Ultimately, what matters most is the comfort level of both the child (now an adult) and the father. If both parties are comfortable with using "daddy" as a term of endearment, there is no inherent issue with it. However, if either person feels uncomfortable or prefers a different term, it's essential to respect their preferences.
Every family is unique, and the choice of terms of endearment should be a matter of personal preference and mutual understanding. As long as the communication between family members is respectful and consensual, there is no inherently "weird" or "wrong" way to address one's parents.