How do I tell my MIL that the stupid toy is broken?

to sum up my MIL, she's a *****, no exaggeration, she's a *****, a few examples are she told my hubby he was shooting blanks, said he should get a sex change and told her husband to punch my husband while he was holding her son and while I was pregnant with our daughter. so needless to say she gets even more bitchy if something she spent her good money on got broken, so last christmas she got my son a drum set, it was for 3 and up and my son was barely 2, it was made of flimsy plastic and has broken, she keeps asking about it! all the time asking if he plays with it, how much he likes it and such, I've been telling her he plays with it all the time but she has this annoying habit of snooping through our house when she comes over and its only a matter of time before she notices its not here, suggestions?