No, it is not directly possible. However, you can add the comment box question with Numeric Input next to the Source question and apply a dynamic show/hide logic on it based on the option selection in the Source question.
Helpfile for dynamic show/hide logic: https://www.questionpro.com/help/dynamic-show-hide.html
Can I add Character Limit to the dynamic comment box used in my survey?
Is data being collected from dynamic texts and comment boxes?