What is the ruling on touching a female's private parts without committing adultery? Is expiation (kaffarah) obligatory, and will Allah forgive him? Is it obligatory to seek forgiveness from the girl's family?

If the person mentioned committed the act before puberty, there is no accountability for him, as the Prophet, peace and blessings be upon him, said: "The pen has been lifted from three: from the sleeper until he awakens, from the child until he reaches puberty, and from the insane person until he regains his sanity." However, if the act was committed after puberty, he must offer sincere repentance, increase his acts of seeking forgiveness and remorse, and resolve not to return to it. He is not obliged to seek forgiveness from the girl's family; rather, he should conceal his own matter.