What is incumbent upon the fornicator if he commits fornication with a married woman and she gives birth to a child from him, and her husband believes the child is his, and is the child attributed to the mother's husband, does he inherit from him, and is he considered a mahram to his siblings from the mother?

Whoever commits a sin and Allah conceals it, must conceal himself and repent immediately by abstaining from the sin, regretting it, and resolving not to return to it. As for the child born of adultery to a married woman, he is legally attributed to her husband, based on the Prophet’s (peace be upon him) saying: "The child is for the bed, and for the fornicator is the stone." He has all the rights of children. However, if the husband is certain that it is not his child, he must disavow him through li'an.