Struggling with my brother’s passing

Assalamu alaikum everyone. I’m not totally sure if I’m looking for advice or just need to vent, but there’s a lot on my mind. Today it’s been two months since my younger brother, only 21, left this world. He was walking back from the masjid after Isha prayer when a car hit him and didn’t stop. We didn’t even know until the next day because us sisters are all married, living with our husbands, and he was the one taking care of our mom. He was five years younger than me, struggling mentally, emotionally, and financially-our dad and stepmom never supported him after he finished high school at 17. A bit of background: our mother has severe schizophrenia and can’t look after herself, let alone kids. When she got diagnosed years ago, she and our dad divorced, and she moved in with her mother, who cared for her for 20 years. So at 17, my brother didn’t feel welcome at our dad’s house anymore and moved in with our grandmother to help with mom and try to start his own life. He wasn’t perfect-we all go through phases-but he tried so hard with our mom. He often felt like he wasn’t enough, like our dad hated him, like he was left to suffer without any guidance. I was really close to him. There were times there wasn’t food at my granny’s house-she was too old to work, mom too sick, and my brother was hustling any small job just to bring money home, sometimes going hungry himself. It breaks my heart thinking how tough he had it. Some nights he’d call me crying, asking why Allah was putting him through this, why life was so hard while everyone else his age had supportive families. Why he had to struggle just to get mom to take her meds or even get out of bed. Meanwhile, our dad remarried two months after divorcing mom, when my brother was just one year old. He had three more kids with his new wife, and by the time my brother left his house at 17, dad was doing pretty well financially. My brother would see his half-siblings in expensive clothes while he didn’t even have decent shoes or underwear. I tried to help as much as I could, but my husband and I had our own bills, and sometimes I’d have nothing to send, and he’d go to bed hungry. It shattered me. For three years he worked odd jobs, carrying a responsibility that wasn’t his, and I kept asking, why him? In all that time, our dad never once checked on him. My brother built up so much resentment, and in Ramadan he showed up at dad’s house saying really harsh things. But two weeks later, he went back crying, asking for forgiveness. He said after praying at the masjid, he felt Allah guiding him to go make amends. That must’ve taken so much courage. I didn’t realize then that this happened during his last 40 days. Looking back, I’m so proud of him. Two weeks later, he was hit by a car just a short walk from the masjid, near our mom’s house. Allah took the strongest person I know, the one who suffered the most among us siblings, and my heart aches that he’s not here with his three older sisters and baby sister. He was our only brother, the one who kept us connected to mom. I’ll never see his smile, his hardworking hands, or hear his voice again. They say Allah takes the best of us early, but why him? Why did he have to endure so much hardship? He’ll never have his own family, never meet my future children, never study like he dreamed. Mom misses him deeply-sometimes she says, "At least my child is with Allah now, not here suffering with me eating dry bread." He deserved so much better. Even when life was unfair, he worked on his iman every day.