My 20 month old doesn't respond to commands. He doesn't talk yet. He is not responding to his name. 

Hearing problem? 
But, he responds and looks at me when I sing any of his rhymes. Wherever he is he will run towards kitchen for some specific sounds like Microwave sound. 

Does he point at things he wants? 
No, but he brings to me or try to bring whatever he wants. For ex. He brings his empty tumbler when he is thirsty. He brings his toy to me when it is OFF(he wants me to turn it On) etc

If the things are out of his reach, he will try to climb or just look at it and groans. 

He doesn't want to make eye contact except when I'm singing his rhymes. 

He pronounced some words when playing. He used to follow commands at 12months, like he moved his body when I asked him to dance or waved when said bye, but now he is not showing interest or he doesn't understand. Not sure what went wrong. Can someone please help?