Several things need to be taken into consideration on this case.........
First, the dude is 18, a dual citizen of both Israel and America, and is currently residing in Israel.
It's also been reported that this young man has a history of mental illness as well as has a brain tumor, which many have had an effect on his behavior.
Why didn't they catch him for so long? Simple...........he was using his neighbor's WIFI to use the internet to mask where the calls were coming from.
What do I think should be done? Send him to trial, and if found guilty, put him down as criminally insane and provide him with the required surgery. If everything checks out after the surgery, put him back out in society.