Nobody drinks coffee AND tea

What does he mean by that ?

It's not meant to ask if someone consumes coffee and tea in the same cup at the same time. It doesn't even mean that someone drinks coffee and tea side-by-side in separate cups during a single meal or snack. The statement is meant to indicate that one is either a coffee drinker or a tea drinker (not to be mistaken for teetotaler... that means something all together different).
I don't agree with this sentiment. For most of my life, I drank both. Granted, I have more varieties of tea than coffee, but for different reasons. Tea can be purchased and stored in smaller quantities. I generally don't purchase more than 3-4 ounces of any tea at one time. Coffee, by contrast, is generally sold in prepackaged bags. I am not a fan of whole beans, but I do generally keep small amounts of ground coffee in a tin and the rest in the freezer.
Not so with tea. Tea is either kept in a small tin or in a small paper bag (with tabs). I only purchase tea from my local teamaster or from a larger vendor that sells tea exclusively. I do not support companies that sell both tea and coffee. Well, I take that back. On RARE occasions (when I am in New York City) McNulty's Tea & Coffee I will make a stop at McNulty's on Christopher Street. It is one of the first shops that I had gone to for good tea and for whole beans. The shop is a throw back to bygone days; they do not measure with a digital scale!
Before I hit the historic retirement age, I decided that I needed to cut down on my caffeine consumption. I refuse to drink decaf coffee. So, these days I will make one GOOD cup of coffee in the morning and also prepare four cups of a tisane for the THERMOS. My tisanes of choice are either herbal blends such as chamomile or they might be hibiscus. I haven't really gotten into rooibos (yet). It seems to have some qualities in common with hibiscus.
According to Wiki : "As a fresh leaf, rooibos contains a high content of ascorbic acid (vitamin C). Rooibos tea does not contain caffeine and has low tannin levels compared to black tea or green tea."
This does not mean that I have totally given up on my beloved black tea. I have a nice sized bag of Scottish Breakfast that I am working on. It hits the THERMOS about twice a week. On such days, I make sure to stay well-hydrated with filtered water; this also helps dilute the caffeine level that is flowing through the body's intake.
I've read about tea drinking practices in the Middle East. It's one of the few times that I would/could honestly say that I prefer the Arabic way of drinking over the Israeli way. The Arabs drink their black tea with dried fruits or nuts on the side. Israelis, by contrast, tend more towards herbals.
"A majority of drinkers prefer strictly herbal blends, not tea leaves, called halitot—infusions. Spearmint is a universal favorite, but other flavors including mint, sage, lemon grass, lemon verbena, and even wormwood are common ingredients. Although not always used, sometimes these delicate flavors are supported by a tea bag of black tea to strengthen the blend."
I like to think of my coffee to tea balance as being a work in progress. Never too old to evolve!