You may request the vadhyar to perform online thru whatsapp call or google meet etc. Or as an alternative, postpone the ritual to next best possible convenient date. If so, then, you may feed crows on that exact date and do the full function on the next possible date. Even after learning the Manthra, you need 2/3 people to perform the rituals, if you or others feel it risky, then above is one of the options. Or you may even go to a place where they arrange and perform this at their place. This is just my humble opinion.