Is it permissible for a father to instruct his children not to bury him with his brother?

There is no Shari impediment to a person's will not to be buried in a specific place or next to a specific person, such as a father's will to his children not to bury him with his brother, especially if the reason for that is the brother's lack of righteousness. This will may be carried out as long as it does not result in harm or the severing of kinship ties among the living.