My Boyfriend has Lupus, and I just don't know what I am supposed to do...

He has been my bestfriend for the last 2 years and after circumstances always keeping us apart we finally became a couple in January, we had about 1 week of happiness and then came constent tiredness, illness and just constent problems around June/July it got really bad it took until August until he was finally diognosed with Lupus effecting his Kidney, originally he was diognosed with Nephrotic Syndrome, I wish that was still the case.

We have both just turned 18. We haven't been out together very often infact our whole relationship just got rushed into the grown up phase. I love my boyfriend more than anyone in the whole world and I just can't stand to see this happening anymore. We have all these plans and I still believe we can have them but how hard is it going to be?
He always tells me we'll get married one day and I want this more than anything, Lupus will not stand in the way of our future together but what will it take away? Will my husband be able to support me, have a career and help father our children or will Lupus take all this away?

I just need help. I can't talk to him about it because it is more unwanted stress but I am stressed too, I am doing my final years exams over the next 2 weeks and find it impossible to study when he is always down.

The last week has been great though, he is really feeling better and we have had a few proper conversations lately which feels wonderful.
He is about to go down to 15mg of predisolone down from 20, what are the effects like at this level are they alot better than 20 or a little? I have read alot of people saying they felt great at 10, I just want 10mg so badly.
I guess I just have to feel lucky because he is having a realtivley speedy recovery. His doctor said it could be only 6 weeks because he progressed so fast but now it has slowed down, still though it has only been 2 and a half months... he worries that it'll drag on for years. I just wish I could help him.