He's going to have to have a full evaluation. Full physical and a bit mental maybe not fully.

He must be at least 50. By that time, there could be some memory problems. Not likely but possible. If he does have ADHD, these problems should be happening for all of his life.

You don't have to have ADHD to get medicated. If you have ADHD, you know you have it. But most people fit the symptoms of ADHD so I think it is important to have a full evaluation but people can't be too serious about the proper diagnosis. It has to make an impact on your life somewhat to consider taking something that has many side effects for most people such as anxiety, blood pressure problems and especially since he's older, there could be heart problems.

Speaking of anxiety, being an accountant is a very stressful job and the side effects of anxiety do mimic ADHD symptoms.

Personally, I don't think someone with acute ADD/ADHD should be medicated. Just my opinion. Using techniques to help. Of course I'm still a mess, even on meds that work. If someone thinks that they have ADHD, I ALWAYS say they might have it and to get an evaluation.

If he drinks lots of coffee, tell him to cut down. For me, it makes my mind even more foggy because it releases adrenaline in the body and doesn't really do anything for dopamine and other neurotransmitter so I don't drink it anymore.

I don't know where you live. But if you live in England, even severe cases don't even get prescribed meds sometimes because there is a strong stigma towards amphetamines. I used to live in Ireland. I didn't get any treatment when I was a kid because they didn't really believe that ADHD exists. They just thought I wasn't trying, liked to talk too much and get in trouble etc..