Bastaard (2019) on Netflix

Plot summary

Daan Van Noey is seventeen, and grief still governs the house where he lives. Robbie, his older brother, died in an accident two years before. His mother, Nina, keeps to the house; his father, Filip, avoids his work. Mother and son meet a homeless teenager named Radja Loens, and Nina sees a way to fill the void Robbie left. She brings Radja home without consulting anyone, and Daan goes along with it unwillingly. Radja settles in. Daan then watches the newcomer take up more and more of his mother's attention, and he starts asking who Radja is and what brought him there.