So I began to search online on ways to help him. A friend of mine is also doing the same thing. And once she showed this to my son. She said "Justin look at my finger....this is b" and she waved her left hand and did a thumbs up. I know that Justin won't understand so I came home and asked him to show me his left hand with a thumbs up and I did this animation for him so that he can see what we meant.
And then I asked him to give me a thumbs up with his right hand.
I showed this to him and will be practicing with him more.
b and d
Once he mastered this, I will move on to P and Q. *fingers crossed*