All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
If a man touches a woman with or without sexual desire, this does not make her prohibited to his son or father for marriage. The woman only becomes prohibited to a man (for marriage) if his son or father married her. Prohibition takes effect upon concluding the marriage contract, even if the marriage is not consummated.
For more benefit, kindly refer to Fatwa 83626.
Allaah Knows best.