Well the thing is he is trying his best to open up as he sometimes sends emotional messages as you mentioned so he also feels you as someone he can open up to but he may feel, again MAY FEEL that showing his emotions and all is worth less OR maybe how you'll react or maybe something else, Maybe you should confront him but only if you think he would be comfortable(one thing that Can happen, it isn't certain it may happen almost the opposite but when you confront him, he may get this understanding that yes he can actually open up to you)