No authority or court (including Apex Court) can condone such delay when delay is beyond extended period and appellate authority is Commissioner (Appeals).
However, please check if Order-In-Original was indeed issued & received by the assessee (i.e. he actually got such order) in the past. If assessee had not got any such order in the past, please ask Dept. in writing to provide 'documentary proof' of date-delivery of such order.
If Dept. failed to provide the same, please again ask Dept. in writing to provide attested copy of such order as assessee had never received the same in the past (by giving reference of earlier request given in writing). You may need to follow-up this request by writing 2/3 letters along-with meeting with concerned officials.
Once you succeed in getting attested copy of such order, you can file appeal with commissioner (Appeals) by treating date of receipt of such attested copy of such order, as date of receipt of original order (which was never received by the assessee in the past).
As a precaution, along-with appeal to Commissioner (Appeals), please also file an application seeking condonation of delay where you can explain entire factual background with proofs (i.e. copies of above-said correspondence with Dept. etc.) that subject order was never received by the assesses earlier and thereby, there is no delay in filing appeal.
These are ex facie views of mine and the same should not be construed as professional advice / suggestion.