The English here is somewhat awkward. A better way to say this is "She and my brother are expecting a child," but then it's not a good translation of "čeká."
That would be "To dítě čeká s mým bratrem". Even in that particular word order it still is more likely that you are talking about pregnancy. To get rid of that ambiguity one would likely say something like. To dítě TAM čeká s mým bratrem" = The child is waiting THERE with my brother.
The original word order above leaves no doubt about pregnancy. Grammatically it might be a waiting child but no native speaker would even consider it be anything else but a baby on the way.