He is a radical islamist. Of course he has mental problems like all other islamists.
Can I expand on your statement? I think the mental problems in the moslem world go far deeper than just the "islamists".
It is a fact that consanguinity (a polite word for inbreeding) in a population will cause genetic diseases, including what we used to call 'feeble-mindedness'. Inbreeding is endemic in islam. And when moslems move to the west they keep their traditions. It is estimated that half the Pakistani population of the UK is involved in consanguineous marriage.
When you start to match the statistics between inbreeding, birth defects, and IQ in certain populations, the corelation is undeniable.
Now, imagine a low IQ refugee in the west. His religion and culture fill him with hatred and rage every day. His friends and coreligionists fan these fires. He is like a time bomb ready to go off. As we have seen over and over, it is easy for such people to go over the edge, in fact they probably see it as their duty.
We have imported millions of these time bombs into our society. The havoc is just beginning.