was dewey always a brother o was he the siguiente 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 mostrar 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.

tu may be thinking of navidad with the Kranks, in which Erik Per Sullivan (Dewey) played the son of the neighbor across the calle 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 tu mean por them telling Dewey to go home, but I hope this helped!