I'm going to challenge a few things you wrote a little bit Bunny. I hope you are ok with that.
And then proceeded to text and tell him what was going on with me and that I thought if he couldn’t be there for me our relationship was not going to be as close as it was.
You are right that what you said could have been a shock to him. He is probably going to need much more time than you think he needs to process all that. I would try to be patient with him Bunny, before issuing him ultimatums (that if he can't be there for you right now, you can't have a close relationship any more). That appears to be using your power, to control the relationship and have your needs met, but healthy relationships are equal in power. I would suggest being patient, and giving him time to process everything you told him, and let him come to you.
but I think he and I won’t be as close.
Oh please don't go thinking the worst Bunny. We all do that, especially when we are feeling low. Sometimes it can lead to self-fulfilling prophecy. Instead, try to refocus your thinking onto all the fun and good times you have had together. Maybe that will lead to something positive.
His reply was basically that he acknowledged I had been through something much worse than he had but that couldn’t deal with facing it and his way of coping was to keep everything swept under the rug... But now in the light of day I’m realizing it’s not fair for me to expect him to face this stuff if he’s more comfortable burying it.
Yes, for sure we are all different, and process information and trauma differently, and on different time lines. Your time line and his time line may be quite different.
He's your brother, and you say you've always been close. Why lose that?
It sounds like you are disappointed you didn't get the response you were hoping for with with your disclosure. That must hurt. I feel for you. But I honestly think that it's important to be patient and give him the "time" he needs.
In the meantime, you can come here for support. There is a lot of experience on this forum, and you have a whole community of support here

Have you ever seen a counsellor or therapist? Many of us do, and if you can find a T that is a "good match" for you, T can make a world of difference. So that could be another source of support, if your brother isn't ready yet.
It's really a positive sign that your brother affirmed that you had it much worse than he did. That was an affirmation right? I think it's amazing that he gave you that. Work with that for now.
Maybe reach out to your brother at some point, and let him know the relationship is important to you. If something in life has been good, it's worth the effort to keep it.
Hang in there. These feelings of hurt and disappointment will settle. Try to look after yourself, and take good care of yourself until you start to feel better.