What can you do about people who don't understand the feelings of others?
What can be done about people who are oblivious to the feelings of others?
「人の気持ちがわからない人」= people who don't understand the feelings of others/people who are oblivious to the feelings of others
※oblivious = 気付かない、念頭にない
「本当にどうしたらいいんだろう」= what can you do about ~? / what can be done about ~?
「人の気持ちがわからない人って本当にどうしたらいいんだろう」= What can you do about people who don't understand the feelings of others? / What can be done about people who are oblivious to the feelings of others?