He had a really hard time in kindergarten making friends and constantly getting into trouble.
I would try to persuade a reluctant partner to test my child with these arguments:
-Testing will help us figure out why he had such a hard time in K, despite being a strong reader.
-Testing may also help you figure out why he's not connecting with his age peers.
-Knowledge is a good thing and will help us understand him better and be better parents to him.
I would test privately, though, with an experienced tester.