....... I'm not sure that I have convinced him to go with a normalized schema but I tried.
I see that here all the time, someone comes in with a problem, due mainly to the construction of the database. I've noticed, often, three or four people will weigh in and reinforce the message.
There are two problems in convincing someone.. The first is it's difficult to see the benefits. The second is very often they've got a lot of time and effort invested in the position they find themselves in. I distinctly remember having done something similar myself when I was first learning!
It's quite easy to forget how long it took you to learn something. However recently I have had my eyes opened as I am trying to learn JavaScript. In essence JavaScript looks quite simple, it's basically the same as VBA you've got the same sort of structures.
However I've noticed there is something different about it, and I can't find any instructions on how to approach it. I think it's a bit like the concept of a collection in VBA. In Javascript (GAS) if you wanted to do something to a column of data in a Google spreadsheet you would access the whole set of Records and operate on them in one go, I can't for the life of me work out how the code works that does that!
I mention this because it's my struggling with JavaScript that makes me realise that MS Access isn't particularly easy to learn and I think it pays to bear that in mind when you answer people's questions.