Hi! I Have Concern About My 29 Months Old Son..

hi! i have concern about my 29 months old son.. he got separation anxiety when my mother inlaw said the he is a bad boy and bad kid everytime when he cry, and my mother inlaw always she saying to my son that their is a man that he getting him when he didnt eat.. i also observe that my son doing tumbsuck, and head hitting and hurting himself.. what should i need to do for my son?