was dewey always a brother または was he the 次 door neighbors son, in early episode they use to ask him to go home, need episode #

Dewey was always a brother. That's why the 表示する is called Malcolm in the Middle, because he was the middle child. I just saw the first episode again on Nick at Nite a few nights ago, and he was definitely there as their brother.

あなた may be thinking of クリスマス with the Kranks, in which Erik Per Sullivan (Dewey) played the son of the neighbor across the 通り, ストリート that hassled the Kranks about Christmas.

Dewey was always one of the brothers. It is shown in the season 2 episode "Flashback" that he was born just after Malcolm accidently causes toxic fumes to fill the house. I'm not sure what あなた mean によって them telling Dewey to go home, but I hope this helped!