If he is still alive he might get easier to call later in the morning as the season progresses. It sounds like you have a roost pattern down and get a sense of where he likes to go later in the morning. When the hens leave him to go to the nests then he gets lonely and will often come to a call. I have actually had my best luck calling mature birds later in the morning away from their roost sites. My calling is quite aggressive and ends with a cackle when I am trying to locate a bird mid morning. I try to stay high and find they come to a call better if I am above them. I walk the ridges and call every 300 yards or so. If I get an answer I cut way back on the calling and tone it down. If he is coming I don’t call much other than a couple of purrs or a few clucks. If he starts to head the other way I try an aggressive call again then shut up. If I go a while and don’t hear him I get ready and start to look behind me because he will often times sneak in the back way for a peak. Good luck with him.