The prefix "dis-" means "to remove or reverse".
In this case, the sentence is saying that if the person doesn't mend his ways, his parents will remove or reverse their ownership of him.
This means that they will disown him. (ഉത്തരവാദിത്വം നിഷേധിക്കുക, സ്വന്തമല്ലെന്നു പറയുക, കൈവെടിയുക)