I found it really shocking. If you looked at how lovely his mum and his brother are and all the normal family photos of Tom looking like a lovely little boy it is hard to believe.
I think he was totally brainwashed. You don't risk your life, kill people, leave your family behind unless you totally believe in your cause. That is what makes this really frightening. He was vulnerable and looking for something and that is what these terrorist organisations prey on.
I felt so sorry for the mum and brother. They felt guilt for what he had done even though they were helpless to stop him. The thing about feeling relieved he was dead so he couldn't do anymore harm was so sad. I think they had lost the person he was before he even left the country by the sound of it.