Are the brothers of the deceased husband entitled to claim their share of an apartment for which the husband paid a small portion of the price, then the wife completed paying the remaining installments after his death with her own effort and money?

The apartment purchased is the property of the deceased husband and is inherited from him, even if he only paid a small portion of its price, because payment of the price is not a condition for the transfer of ownership. The remaining price is considered a debt upon him, to be paid from his estate before its division. If the sister paid this amount and did not donate it, then she has a debt against the deceased, to be paid from his estate. The estate (including the apartment) is divided according to the legal shares: one-sixth for the deceased's mother, and one-eighth for the wife due to the presence of a lineal descendant, and the remainder is divided among the rest of the heirs (the male receiving the share of two females). If the deceased left nothing but this apartment, the heirs can agree to divide its usufruct or sell it, and the sister collects her debt from the sale price, then the remainder is divided. It is necessary to refer to the Sharia courts in matters of inheritance due to their seriousness and complexity.