"Is a marriage contract valid if witnessed by the wife's brother and the husband's brother, with the presence of the guardian and the rest of the family? "

"The jurists differed regarding the testimony of siblings on the marriage contract of their brother or sister based on several opinions:

Hanafi: They permitted their testimony and the contract is valid with it initially.

Maliki: They did not permit the testimony of someone who could be a guardian for the wife.

Shafi'i: They permitted the testimony of siblings on the condition that no other guardian is appointed in the contract.

Hanbali: They permitted the testimony of those not from the direct line of descent unless the witness is a son of the guardian.

The predominant view is the validity of the contract with the testimony of siblings on the condition that none of them are a guardian for their sister. This aligns with the Hanafi, Shafi'i, and Hanbali schools of thought with their stated conditions."