I never considered that I had adhd until someone jokingly suggested it at work, at first I was a bit offended as I had misconceptions of what adhd was. A friend was diagnosed and again suggested I might have it so I started researching.
It took me a while to look in to it and I’m really glad I did now as it has helped me explain a lot about how my brain works and how I react to situations.
Your friend may already have had a diagnosis but might not want to share it with everyone due to the stigma that surrounds a diagnosis and misconceptions about it. If he doesn’t have a diagnosis suggest that it might be helpful if he spoke to his GP about it.
I would talk to him when he is calm and not frustrated with work stuff. Just ask him how he is feeling and mention that he struggles with frustrations and talks a lot and ask if anyone has mentioned this before, he might say it’s new since starting this job or he may say I’ve always been like this. He maybe willing and open to have a conversation, just remind him that you’re his friend and you like him you’re just concerned about how he deals with things.
Stick with him as a pal and reassure him that it isn’t criticism it’s concern. He may take the conversation well or he may be upset and distance himself, you have to understand that he is processing the information and adhd brains don’t react well to critisim and tbh most people don’t 😂 so just stick with him as a friend and support him best you can.