Doctor's pocket

Today's creative offering was a doctor's pocket.  
No.2 son: "Can we play doctors?"
Me *naively*: "Of course!"
No/2 son: "Do I have a doctor's costume?"
Me *nervously*: "No. But you have a doctor's kit."
No. 2 son: "What I really need is a shirt with a large pocket to hold all my important doctor's things."
Me: ......."I'll get needles and thread"