Is it permissible for a person to go out and walk with his female relatives who do not observe the full hijab, and is he sinful if someone sees them or hears their laughter?

It is permissible to go out with a woman who is immodestly dressed (mutabarrijah). She should be advised and guided. A person is not held accountable for the sin of another, as Allah Almighty says: "Every soul, for what it has earned, is retained." And the Messenger of Allah, peace and blessings be upon him, said: "Indeed, no offender commits an offense except against himself. Indeed, no offender commits an offense against his child, nor does a child commit an offense against his parent." The advice should be given gently and kindly.