Sorry to hear about your situation, there are thousands of families in the same situation unfortunately due to the obvious know reasons to all.
I believe your son's I485 petition also has been applied in Oct 2020.
Why do you think he is going to age out? As per CSPA Age calculation, your son's age at any point when the visa numbers are available is going to stay as 18.5 Years based on the AOS filing date.
https://www.uscis.gov/policy-manual/...rt-a-chapter-7 - Refer to "2. Child Status Protection Act Age Calculation" under "F. Family and Employment-Based Preference and Diversity Immigrants"
Only benefit you might have is to get the card earlier if EB3 moves faster than EB2 which no one can predict. Take an appropriate decision weighing all facts.