You should offer sacrifice or udhhiyah on behalf of deceased parents if they have a made will to that effect. Otherwise, it is better to give charity on their behalf rather than offering a sacrifice.

I am not saying you are not allowed to offer sacrifice; you may do it; however, charity if preferable. When asked about the good deeds one can do on behalf of one’s parents, the Prophet (peace be upon him) mentioned charity and not sacrifice; it is for this reason that we find the pious predecessors were in the habit of opting for that instead of sacrifice.