If you can't get special bags, my personal illness kit was always a stack of grocery store bags (the recyclable kind), a roll of toilet paper (for wiping my mouth, etc), and a bottle or two of water (for getting rid of the taste). I had bad panic attacks prior to cancer (not so bad now), and got pretty sick on a regular basis, so I carried a kit like this in my car and stuff in my tote bag all the time. Usually had a place to dispose of stuff, so it wasn't going round trip with me ... I suppose some sort of scent-dampening bag would help ... but it helped a lot just to know I had stuff handy. Back then I'd say a mint for afterwards would help, but with OC, mints burn once radiation kicks in, so definitely not that ... maybe a Vitamin C drop or other hard candy to suck on, if he wants flavor and can handle something in his mouth.
That's my instant nausea kit, anyway.

Hope you don't need one, but if you do, it's a quick and cheap way to make one.