Where is this condo your brother was planning to rent? SGD4,500 is equivalent to Bht108,000 (using 24.0 as rate)
I'm guessing that is inclusive of the security deposit & 1 month's advance rent? Even then its a pretty hi-so place to be charging that much!
If you think you have been scammed and want to expose this scammer (Guilty until proven innocent? Or innocent until proven guilty?) Please write a proper FR what happened. Feeding info piece meal is a tease which should only be done at a go-go.