The certificate of EWS is valid for one fiscal year. So if you have issued it in the December, 2020 then its valid till March 31,2021. So your friend is saying the right thing. As per the government instructions, an EWS certificate is valid only for one fiscal year.

The eligibility for the EWS certificate are:

• The annual income of the family of candidate should not exceed 8lakh per annum.
• The family should not hold 5 or more than 5 acres of land.
• The family shouldn't have a residential area more than 1000 sq feet.
• The family shouldn't have a residential plot (in notified municipalities) of an area 100 square yards or more.
• The family shouldn't have residential plot (other than in notified municipalities) of area 200 square yards or more.

I hope this answer helps. All the very best for your future endeavors!