this makes it seem more like a personal to you question. like youre asking how you should treat your sibling(s). we dont know you especially your sibling(s) so if this is what youre referring to my answer is going to be try to think of something you all enjoy, spend time together.
if youre asking about other peoples situations, i would love to take my brothers out and treat them like the princes i know they are. ice cream, toys, they name it its theirs. however i cant and they most likely wont even know of my death. the eldest is only 10 and they both still live with 'their' parents, people i refuse to ever contact again to the point that if they contact me i WILL get a restraining order.
i hope this helped answer your question.