He was so happy while his childhood? 請問這個句子可以這樣寫嗎？

so---adv of manner;so-----that,--->>with the intent that, with the result that ; in a way that:-
For the complement of be , seem , feel ,"very" is used.
while---period of time ; for a long while ; for this long while past ; for a while ; in a little while ; soon ;
eg:-It so happened that he was (very) happy (no while) in his childhood.
eg:-He had a happy childhood.---have used in the past tense=had
eg:-He was very happy in his childhood.

He had a happy childhood.

while 通常指不長的一段時間，如童年長達數年，不是合適的用字。
如是要如原句的寫法，建議寫成
He was so happy (when in) his childhood.

He had been so happy during his childhood. Yip