aeh's words of wisdom have been invaluable in our own double 2E journey, so I'll just highlight a couple of key thoughts from a parental perspective.
1) Five really is young for reading and writing. Lots of kids, gifted and neurotypical, aren't there yet.
2 BUT - pay attention to the things that set off your kid's behaviour. I wish I'd understood way sooner that DD's nightly freak-out about her school reader was much more important than the fact that she seemed to be able to (eventually, when she calmed down) read the book. Anxiety, anger, avoidance, behaviour - all are ways your kid is telling you that there is something painful about the task you've given them, and they are panicking.
3) 2E kids are really, REALLY good at looking like they can do things they really can't, or can only do with great pain, using all their resources, or when the planets align. The question is less, "Can they?" and more "At what cost?"
4) My dyslexic DD when tested at 8 had great phonemic awareness (88th percentile), but scores plunged when she was asked to engage in increasingly complex manipulation of those phonemes - which aeh identified as a common pattern in 2E. She was probably the best "pre-reader" in her K classes, but she stopped there, while her peers moved on in grade 1. (Ditto for writing.) Detailed phonemic assessment (like a CTOPP) can help untangle this. 2E kids often don't look much like the typical descriptions of various LDs, but there are some great threads on this forum we can help you find if you are looking for more info.
5) Writing letters requires a different part of the brain than drawing, and kids can be happy artists while also dysgraphic.
6) Ross Greene is amazing, and I can't recommend collaborative problem solving and his advice on
https://www.livesinthebalance.org/parents-families enough.
Sending lots of best wishes to you and your son.
