His direct training was in Sunni Djakarta. Moslems don’t ho around to different sects. They stay with the one they started with except a few will “convert” at the point of a sword. Mostly sunnis and shias, because of that, don’t try hard to convert each other and they don’t keep prisoners as prisoners. They either sell them or kill them or enslave the women and children.
It’s my understanding that his father and relatives in Kenya were Shia. Just because Djakarta was mainly Sunni, it does not mean that there were no shia there. Look at Iraq and Syria.