Legal heir certificate

My Dad passed away few months ago & am in the process of procuring legal heir certificate. We have submitted all the required documents , but the village office says the one of the deceased siblings have to come personally to village office to certify the relationship. Now the problem is his siblings are all bedridden or too old to step out of the house. We have informed about the situation to VO, but they are adamant that rules cannot be changed. Any help?