Brothers

Two brothers, Shunpei and Kyouhei, have very opposite characters but share a crush on their cute sister Anko. The three of them live with their excentric father, may (or may not) have diffferent mothers, have fun, lots of tantrums and try to lead a happy life in junior high school.

From Omanga:

Eiji Otsuka and Sho-u Tajima at it again, Eiji in a much more minor role this time, however. In any case, this a relatively older and short comedy series (4 volumes) that should be a fun break from their usual mayhem with MPD (Multiple Personality/Dissociative Identity Disorder) .

In 1994, this manga was published as a whole under title "BROTHERS High School".