I have already enough talk with my family to explain which charger and cable goes to which phone.
Even more humiliating is them looking at me as if I was complete idiot after me suggesting to them that the selection of cable itself may be cause of their problems. They had some physics at school and from their point of view the cable is just a bunch of copper and it should absolutely make no difference for how fast their phone charges.
Now I have to ready myself to have those "Universal" chargers which can only ever charge a single device but with no indication as to which device they can charge or which cable you have to use for this to work.
Which is pretty ironic because right now we have a bunch of laptops and it is much easier to explain that if the plug fits the socket you are ok and if it does not you need to look for the one that has matching plug.
The only solution I see is labeltown -- dust off my label printer and have every single piece of equipment, charger or cable clearly labeled.