200 mg of zinc sulphate a day would not be a dose for anyone with a sensitive stomach. He would be lucky to get by with 10-15mg of the zinc sulphate form at a time. New chapter or megafood zinc(cultured vitamins) would be the easiest on the stomach and with these brands might be able to take a little higher dose than 10-15mg. I would be careful with any other brands as it might not take much to upset his stomach. High doses of zinc for long periods of time can cause copper imbalnces so I would be careful with that.
What supplements is he taking right now?
How much extra calcium is he taking?
Calcium supps can cause indigestion if taken with meals(bufffers acid production). Calcium is just plain hard to digest. Excess calcium can create a favorable alkaline environment for fungal candida and cause constipation. Careful with overdoing the antiacids especially at mealtimes. You don't want to buffer too much acid then that can lead to indigestion. If he does chlorophyll or greens powder=in between meals/empty stomach. Some can have issues with chloropyhll supps.
If he has a stomach sensitivity I would go with new chapter brand or megafood. These brands seemed to work better for people with sensitive stomach/gut. This is the feedback I got when I was vitamin manager at a health food store.
Some enzyme supps can cause GI irritation for people that are have sensitive guts.