To bully / Pick on : ضايق
he is being bullied by the other children at school
يُضَايَقُ من طرف زملائه في المدرسة (Passiv Voice)
If you want to say it using the Active voice :
يُضَايِقُه زملاؤه في المدرسة
they picked on him because of his temperance
ضَايَقُوهُ بسبب امتناعه عن شرب الكحول