"That richest person's mind is dull."
Translation:Orang terkaya itu otaknya tumpul.
Bodoh is stupid, dull can mean not stupid but not creative or bright.
I criticize the use of otak which is brain, maybe pikiran, budi or benak is better.
On the English side that should be The if the person really is the richest, but I would guess terkaya may mean more extremely wealthy.