Sahm home schooling moms help

My son is 4 every day I work with him on his numbers and his letters every day when my husband comes home and asks him to count to 20 he legit won’t count to 20 he acts a fool and starts saying what’s after this number etc etc

It’s like he doesn’t retain the information that I’m teaching him and it’s starting to worry me

Idk what to do anymore then since I’m a sahm my husband looks at me like I don’t teach him anything. I have one other kid and another on the way and I’m just worried when my newborn comes I’m not going to have much time anymore like I have been

He’ll look at a number and know what that number is he can match the number of dots to the correct number ex 4 dots he knows the number 4 goes there but he won’t count to 20