Shouldn't there be für or something? Ich suche für meinen bruder? I mean how do you say I search my brother?
'I'm searching my brother' got rejected while I feel it's also correct.
No, it is not correct.
"I am searching for my brother" = I do not know where my brother is. I am looking in various places to find my brother (e.g. in his room, in his car, at his school, at the park, etc.).
"I am searching my brother" = I am trying to find something. I am looking in various places on my brother in order to find that object (e.g. I look in my brother's left pocket, in his right pocket, under his shirt, etc.).
"I am searching for my brother" - "Ich suche für meinen Bruder" or "Ich suche meinen Bruder" "I am searching my brother" - "Ich suche meinen Bruder" or "Ich durchsuche meinen Bruder". Both are valid translations in German.
The part where you search "on" your brother is ambiguous in German. Like so many things.