Getting married is indeed a happy thing. You can give your brother a customized personalized name necklace as a gift. You can give a pair of very creative gifts. Engrave their names on the necklace, which symbolizes that they can grow old together forever. Now many couples will customize this gift.
After getting married, those daily necessities must not be bought together. As a sister, you can buy some daily necessities or kitchen supplies, or give gifts such as home appliances. It is best to give your brother something that he has not yet configured. It can also make him feel your sister's heart. Like electric kettles, induction cookers, dishwashers, and sterilizers are all fine.
The air in the new house must be bad, so you can give him an air purifier to prevent the harm of formaldehyde and benzene. You can also give some home decorations, such as large posters, or if you have time, you can embroider a cross stitch for them.