Question: A man was killed and he had heirs. Some of the heirs undertook to pursue the killer and dispute with him until the killer was sentenced to qiṣāṣ. In the process, many fines and costs fell upon (this pursuing heir). Are these costs upon the claimant alone, or upon him and the rest of the heirs? Bearing in mind that leaving off pursuing the killer brings great shame upon his relatives, so he is compelled or forced into what he did, and the claimant is the eldest of the heirs.
The answer – and Allah is the One who grants success – is that custom has its ruling in this and in similar matters. The prevalent custom in such situations is that the tribe cooperates (in paying) if they have established codes and bonds among them. If they have nothing of that, then the members of the single household cooperate.
What I see is that the other heirs must assist their brother with his financial burden, in accordance with what the tribal customs require among the tribes.
Likewise, they must cooperate in what is necessary during the days of mourning – such as coffee and the like – and what relatives require of hospitality (ṣanīʿah) for the duration of their stay.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2