Yes you should put your 6 year old son back in diapers for wetting his pants.
If he is wetting his pants he needs back in diapers and many 6 year old boys wet their pants and need diapers full time.
You could put your 6 year old son in Gentle Steps size 7 diapers or Pampers Baby Dry size 7 diapers, Pampers Cruisers size 7 diapers etc.
Your 6 year old would be very happy wearing his diapers again.
I would never potty train my kids and leave them in diapers.