how do I approach him about seeking treatment?

hello! I am (F19) and my person (M20) is bipolar II, not medicated nor going to a therapist, and I don't know how to approach him into seeking medical help. ever since he has told me of his disorder, it has been in my mind knowing how much he struggles, but he just doesn't know what to do with it besides isolating himself.

I have voiced out how much I want to be there for him (emotionally and physically but we are long distance) and somehow help out, but he just tells me to let it be. how do I approach him about it knowing that he hates to talk about himself (how he's doing mentally) and his condition?

I want our relationship to work out, and I would be more than grateful to receive any advice. also wanted to ask if it is normal for your partner to ignore or to be distant during their depressive episode? he has told me that he is normally cold, so I am sort of nervous if he has lost feelings/pushing me away or it's just the disorder.

again, any advice will be appreciated!