Does he know that I'm his Mommy?

We have a 2 year old son with mild CP who is being raised by his paternal grandmother (not our choice). Sadly, we don't get to see him very often because of a deep family rift and legal red tape, etc. However, he calls me "mama" and my husband "dada". Does he really know that we are his parents? At this age can he connect the word to the person with understanding? Can he sense that we love him? We have been there for him his whole life - he just hasn't lived in the same house. Thank you for any sensitive answers - this is a matter close to my heart.