I had a bit of an addiction to these myself years ago and it is definitely not easy to stop.
I have an uncle who takes a truely scary amount of Solphadeine tablets, everywhere you look around his house, there are empty glasses with the residue of soluble Solphadeine in them, empty packets all over the kitchen worktop, the door pockets of his car are stuffed with spare packets, it's horrible, must cost him a small fortune and will kill him but there's nothing I can do if he won't admit to having a problem in the first place
Thats pretty blatant. And I'm sure you know as much as me, he's going to have to face up to it sooner or later
It was a bit more furtive a thing with me, I had a public box that went down slowly and a lot more hidden away I was getting through, I think it was always something I knew wasn't good and was quite embarassed but not enough to stop taking them. I had a secret stash wherever I was, strips hidden in soap bags, saddlebags and bar bags, back of cupboards, in the wardrobe, every coat or softshell pocket had them in & I had either a bike bottle or a sparkling water bottle always around when out so it didn't show or look unusual to have something fizzy on the go. I was always quite careful about washing the glasses up atnhome and work too as its pretty unique a dirty glass look.
I can empathise with the not admitting to it being a problem, the bloody things cause more pain than they cure after not long at all so they become a self fulfilling necessity in your head - I'm in pain reach for the Sollies, quick drop in the pain and then it's back so reach for them again, and 2 every 4 hours soon isn't enough so you're over dosing yourself just to mask the pain that they are causing and taking more tabs causes more pain...... & it is the same narcotic family as morphine & heroin so is pretty clingy stuff when it gets into you
Having been on and off codeine for a number of years (migraines was the excuse I used - even with being on prescription meds for those) before really getting stuck in it this time I've finally twigged on it isn't something I can pretend over or stop/start with, it's got to be nothing at all ever & I'm gonna have to MTFU when I get a pounding head or the knee plays up.
I'm also going to be careful with drinking too, they seem to have stripped away my already lightweight ability to cope with alcohol without a hangover, A can at home or pint in a pub will give me a headache now.
Compared to smoking though it's dirt cheap, I'd spend 10-15 quid a week average (around 100 tablets) a bit more on a bad week & I bet he'll have a network of chemists he uses so he's not going into one or two responsible ones too often and getting remembered.
There's something about it being soluable and Solpadeine too or the Boots codeine plus variety as they both have caffeine in them that *works* better than the cheaper Paracetamol and Codeine only ones, both for pretending to dull the pain and as a narcotic hit, in solution works so much better than capsules or pills too. I guess in a smoking sense, everyone has their favourite brand of tobacco and level of filtering.
I hope your uncle sees the light before they eat him away completely.