1130. Introduction They are called ‘aṣabah, which comes from tying and strengthening, because they support one another and bail one another. As always in Islamic law, they are given rights that correspond with the obligations upon them. The maternal side of the family of the deceased were not required by law to bail him out if he killed someone by mistake or needed to pay the diyah (indemnity) for an injury, etc.
‘Aṣabah could be translated as universal heir, but I chose residuary heir because it is more descriptive of the way their entitlement is determined. They will only take the residual part after the heirs of designated shares take theirs.
It may sound like they are all less deserving than the heirs of designated shares. While that may be mostly true, one of them is the son of the deceased. There will never be a case where he will not have anything left to inherit, because he will completely block all the ḥawâshi (brothers and uncles and their children) and will partially block the parents, causing them to only take 1/6 each. He will also partially block the husband/wife, causing them to take 1/4 and 1/8 respectively. In his presence, it is not possible for the designated shares to be more than 1/3 (or 4/12) for both parents + 1/4 (or 3/12) for the husband, making 7/12 in total.