Yes, your adopted son can call you "dad" in Islam.
Islam encourages strong familial bonds and emphasizes the importance of raising children with love and care, regardless of their biological connection.
While adoption is not explicitly mentioned in the Quran, Islamic scholars have interpreted various verses to support the practice and the rights of adopted children.
The Prophet Muhammad (PBUH) himself adopted Zayd ibn Haritha, and he was treated as his own son.
Therefore, your adopted son calling you "dad" is perfectly acceptable in Islam, and it reflects the strong bond you have built.
It is important to remember that Islam emphasizes treating all children with kindness, respect, and love.
Therefore, fostering a loving and supportive family environment for your adopted son is crucial.