Yes, you'll feel normal again.
Your grief isn't a new part of you. It's your love for your brother, and right now that part hurts so much it's all consuming. But it'll die down.
Think of it like you've broken your leg. In the moment, it's agony. By the end of the day, you've learnt to live with it. You're taking painkillers, you're on crutches, you've got your leg in plaster. A few weeks later, it's healing, and within 6 months it's a dull ache that bothers you in cold weather.
Grief takes a bit longer, especially for someone you're got a very close relationship with. Right now, you're still in the agony. But at some point, you'll learn to live with it. My "crutches" involved trying to take my mind off it by going on rollercoasters and taking on stupidly big DIY projects (along with too much alcohol). Yours will be different.
But at some point you will start healing, and you'll be able to get through the day without your crutches. It'll still hurt, but not as much, and you'll be able to forget about it for periods of time. And then at some point you'll be able to think about him, remember the good times without it hurting at all, and it'll only really be painful at certain times or certain places, like on his Birthday, or in his favourite restaurant.
Think about how much you thought about your brother when he was alive. He probably popped into to your mind across the day, maybe some days you didn't even think of him. That's what your grief will become over time. The love of your brother and the pain it's causing you right now will shrink back down to take up the space it did while he was alive. You'll keep feeling it as pain for a long while, but less and less overwhelming, and one day you'll be able to poke that spot and mostly just feel the love for him, just tinged with the dull ache of sadness.
And you'll feel normal. Just like feeling that dull ache in your leg in winter feels normal.