Hi everyone! I THINK this is a right section as it concerns kids.

Anyway I am planning to teach my little brothers (8 and 12) English. Coming from a Malay family, we don't talk English much. As Im on my semester break Im planning to teach them basic English (grammar, verbs etc).

The problem is I don't have a structured..syllabus and therefore don't know where to start. So.. Any suggestions would be very much appreciated

Start by conversing with them first. The formal structures (grammar etc) can come later.

Or you can ask them to read the paper aloud.

Your brothers 8 and 10yrs old? Shouldn't they already schooling? Guess they already have exposure to English eventhough are from Malay family, right?
Try to see what is your brothers' English level, if you found they need to start/re-start from very basic. There are plenty of English books meant for beginner.
Another easier teaching method is to encourage them to read out loud English newspaper. And to make learning fun.. teach them to listen to English songs.