What is the legal and Sharia status of the questioner's father and of the claimant who claims to be their brother, and is her father legally obligated to undergo tests to prove the lineage of the claimant who was born 6 or 7 months after his mother's marriage to another man, following her divorce from the father?

If the "Fatiha" was merely a sermon without a legal marriage contract, then the child is not attributed to the father, but rather to the mother, as he would be considered a child of zina (fornication). However, if there was a legal marriage contract, even if undocumented, then the woman is considered his wife. If he divorces her and she marries another man, and she gives birth to a child after six months, then the child is attributed to her second husband. DNA analysis is not considered valid for establishing or denying lineage. In matters involving disputes, a mere fatwa (definition) is insufficient; rather, one must refer to the Sharia (definition) court for a ruling.