Do not sell beer to this guy.
Most, but not all. Here in Pennsylvania only the government is allowed to sell hard liquor or wine* (something our governor want’s to change). You can buy beer from a distributer by the case or keg, or by the 6-pack from a bar or restaurant as an off-sale (in which case you can’t buy more than 2 at a time, but are more than welcome step outside then come back in to buy more). Recently some supermarkets have gotten their cafes licenced as restaurants so you can buy beer there (& they’re also* required *by law to let you drink it on-site. Back to the OP we have the same restrictions on making off-sales to the intoxicated and every place has signs warning customers that “VIPs” (Visually Intoxicated Persons) will be denied service.
*In-state wineries can sell their products direct to consumers onsite, and can operate a limited number of “satellite shops” selling only their own products. Same deal with hard cider. Nobody can have alcohol shipped to their home.
It’s been a while since I worked in the liquor industry, but IIRC it’s basically pubs/hotels/nightclubs/RSLs/Sports Clubs etc, bottle shops/liquor merchants (using the liquor licence of a hotel they’re at least nominally affiliated with), wineries/distilleries/brewers, and restaurants/cafes with a liquor licence. There’s probably a few others I’ve forgotten, but the edited highlights are Convenience Stores, Petrol Stations, and Supermarkets are absolutely not allowed to sell alcohol in Queensland. No distinction is made between wine, beer, and spirits IIRC- it’s all alcohol.
There’s also what’s called a “BYO” (Bring Your Own), permit whereby the premises aren’t licenced to serve alcohol, but patrons are allowed to bring their own (purchased elsewhere, and traditionally only wine) and the establishment charges a “Corkage” fee and provides wine glasses. These are issued at the discretion of the local city/shire council and are fairly straightforward- you’ll often find smaller restaurants with a BYO licence.
Each state’s liquor laws are slightly different in minor respects- in NSW, for example, some supermarkets have a bottleshop in them so you can effectively buy alcohol from the supermarket, but it’s not allowed in QLD- but generally the rules appear to be the same everywhere for the most part.
It was certainly interesting when I was in Malaysia and Indonesia (both Muslim countries) where I could buy beer from 7-11s, convenience stores, supermarkets, and petrol stations at all hours of the day and night without any issues at all- just help yourself from the fridge and pay the nice person at the counter- but here, if I want a six-pack I have to go to the bottle shop or liquor store and they all generally close by 9pm.
On the other hand, having seen how Queenslanders drink, I can sort of understand why you can’t get alcohol from the supermarket here. 
The police in uniform law has been scrapped. There are two other restricted categories IIRC.
1: Known alcoholics
2: Suspected prostitutes
3: Hi Opal 