Ive found a better monster for you took look at for you to see how to make your child react to receiving something. Its the armourer at /room/lindos/npc/armourer.lpc

In the first job you get from the job knight the job involves giving the armourer an order then he gives you a receipt back. You can see how it works in the 'give(str)' and 'hasorder()' procedures. 'give(str)' is called when he gets the order. Then 'hasorder' is called to create the receipt if the armourer finds that he is carrying the order (present("order",this_object()); ).