
its not that he can't "feel" emotions its that he doesn't understand them. he knows what confusion anger and hate feels like because he has seen and felt but its the other emotions (love joy loneliness sadness fear) he doesn't get thats why he said he felt empty when Chise was gone.
So for ex: if emotions were a book and every page you read you get a definition of what they are but if you never experience them how would you know that you have felt them? This is what Elias means he has been reading the book but not experiencing it.
i hope this helps explain but for a more in depth dicussion please message me. (=・ω・=)S

true and i understand sometimes translations are not worded right mostly because translating manga into other languages is hard especially when a word can be said in multiple ways. but after reading this multiple times i can understand what Elias is going through. he is like a child, even though he has lived for many centuries, who has much to learn about emotion/feelings (oh the feels lol). i hope in the next chapters we can see him develop more and hopefully find out what being he is... (guess he is a demi-god or god that was created for some purpose! (=・ω・=)S )
I was rereading chapter 19 and thinking about how Chise didn't point out to Elias that he claims that he can't feel what humans feel, but he's been doing so this whole time. (Getting angry when he thought she was killed, feeling shame, embarrassment, joy, love?, curious, and now loneliness)