How do I communicate he needs to get treatment?

My boyfriend and I of 7 years are taking a break. He (John) has move out for 6 months. He has ADHD and I've always known it. He took medication in the beginning, but hasn't for the past few years.  I never thought about it in terms of effecting our relationship. I never took ADHD seriously. Honestly, I thought "Oh ADD... everyone has that." However, now that we are trying to decide if we should stay together and work on this relationship or break up, I started doing research about some of our problems. I came across a website about Adult ADHD and relationship and I nearly fell out of my chair. John has 90% of the symptoms listed on the adult ADHD sites... procrastination, chronic lateness, distracted easily, hyper focused on video games or jeep forums (obsessed for hours and hours at a time), can't finish sentences (he gets half way through a sentence then just says... ummmm... ummmmm.... and then the thought is gone and he is off thinking about something else - happens all the time), easily frustrated.... and so forth. Then I read about the relationship problems and I started crying. It was hitting the nails right on the head. John says inappropriate things sometimes. He snaps at me easily. He can completely ignore me for hours --- then suddenly want to be intimate (and I'm like you just ignored me and now you want me to be all over you?), he has trouble understanding my emotions, he cannot plan anything (he buys gifts the day of or days after holidays or birthday --- no surprises... no special trips), he is so focused on jeeps right now that its all he does or talk about or reads about or anything --- I'm like how are jeeps so much more important than me... and so forth. We are breaking up because he relates love to sex and our sex life has severely diminished.  Its because I am emotionally unsatisfied and he is not committing to me (can't plan - has no idea what he wants - his thoughts on the subject are all over the place). Also, he is bored in the relationship (also a symptom I read about) and he is restless in our routine. Its a horrible cycle. But what I've discovered is that he is really suffering from ADHD and I am having a bad reaction to his symptoms. He is not being treated and I think the first step to our reconciliation is that he gets treated so he can sort through his flux of intentions and feelings and create a structure in which he can start getting better.

We love each other. We are best friends. We love being near each other. I want to make this work. And now that I know we can work on getting treatment and I can better understand his symptoms and not take them personally - I think it can get better. I feel horrible for never researching it or taking it seriously before.

I decided first I was going to talk to a therapist, he suggested I write an email about my concerns and let him know I am open to talking about it. My therapist will edit the email before I send it to John. BUT what should I say? I do I say I think you need treatment? Does anyone have an example of a good letter written from a loving partner of an ADHD person?