Some/most OTAs will allow you to cancel within 24 hours.

If a 24 hour grace period is not applicable and you are sure that your father didn't actually book these dates, I would escalate it/make a formal complaint. You may contact the credit card issuer and dispute the paymemt on the basis that your reservation does not reflect what you booked/purchased (whether the credit card company will side with you on this is doubtful).

You need to sort it out with the OTA; not El Al.