Will the deceased father be sinful if his children play music through an audio device he owned during his lifetime?

There is no sin upon your father if you use the device for disobedience, for the sin is upon you alone. This is because a person is held accountable only for their own deeds, and does not bear the burden of another, as Allah Almighty said: "And every soul earns not [anything] except for itself, and no bearer of burdens will bear the burden of another." The device can be used for good or for evil, and if you use it for evil, the sin is upon you.