So glad to hear of the improvement!
Are you using the Cetaphil cleanser or lotion? It's easy to get them confused -- one year my mother in law gave us tons of the cleanser instead of the lotion, bless her heart. That would probably dry him out.
There could be several things going on with his face, if it isn't the Cetaphil:
(1) Since it has been so hot, the air conditioner or fans may be drying out his face.
(2) You may be seeing old skin that has built up coming off.
(3) He may not be able to tolerate washing his face every day.
(4)It could be the Aveeno -- that dries our daughter out really badly (she can only tolerate the Aquaphor wash).
I would suggest switching the face wash first, and seeing how that works for a week. If you don't see improvement, then switch out lotions. If that still doesn't work, try adjusting the number of times you wash his face. If that still doesn't work, you might need to beef up his face lotion with glycerin or adding another oil to his Aquaphor (blending Aquaphor and oil in a blender makes it less greasy, btw).
Their skin changes so much even day to day that you really just have to breathe deep, be patient, and keep at it -- much easier said than done!
4 year old daughter with CIE