ANSWER:

He should not allow such non mahram women to look at his photos and follow him if such photos are personal and his social media platforms are not Islamic or used for spreading beneficial knowledge. 

This is one of the steps of satan 

My friend has women following his social media account, but he does not follow them back. His wife strongly dislikes it and he justifies it saying its halal and he isn’t sinful as he isn’t following them back. But his wife is upset and says he doesn’t care about her feelings, and she wants him to remove them, as she doesnt want other women to look at his pictures. What is your advice for him?