How to Be a Better Partner/Friend to Someone with Chronic Illnesses?

My boyfriend of 2 1/2 years broke up with me recently. We love each other so much, but it’s more clear than ever that him having ADHD, Type 1 Diabetes, and Grave’s Disease is taking a bigger toll on him than I thought. He just doesn’t have the energy to commit to a serious relationship at least for the time being and it breaks my heart that he’s going through so much.

I tried seeking support regarding this while we were dating, as I wanted to be the most supportive partner possible, but I didn’t know how to go about it. Either the sources I used weren’t really helpful or I would forget what I learned. Despite us breaking up, I still want to be in his life and be a supportive friend. I just don’t know how. He seems fine a lot of the time, so I often forget what he’s going through and I know that is frustrating for him.

If anyone has ADHD (I know this isn’t a chronic illness), T1D, and/or Grave’s, please let me know things that you wish your partner (or anyone around you) would understand about you and how they would better support you. General advice is welcome as well, but the more specific to his situation the better! Thank you!