Well, I think it's better to wait for parents to come back before celebrating birthdays together. After all, birthdays are better when everyone is around. Children's birthdays are actually very important. Of course, if you are taking care of him yourself, you can also buy him a small gift first, wish him in advance, he will be very happy, you can give him something he likes, at this age he will like sports, give him a ball.
Or make a real-life cartoon version of him, which can be regarded as a souvenir for him in the future. When you think back, you will feel very warm. Wait for parents to come back and then celebrate his birthday properly. I hope it helps you, haha, come on. . .
7-year-old children must like to play, you can buy a bicycle for your brother as a birthday gift, so that your brother can exercise while riding outside, and it must be good for him to exercise after finishing his studies!