Mom in law is the one who buy the dried crocodile meat etc. She buys them from Sheung Wan.
My brother gave me the stethoscope coz he's a doctor himself. I think you can buy them from the medical supplies shop.
With the stethoscope I can hear his breathing. If he's wheezing I can clearly hear the wheezing sound. And also I can tell if his in and out breathing is normal. If he's wheezing the in breathing would be short and sharp.