Let me to be clarified to see If I understand, please correct me If I'm wrong. After the phone call, he basically statement that you have to do it it something you hated it because that is the responsibility of being strongest person to fight for the world. Is he referring to himself or MC? If he referring to MC, then why he said that he won't let him enter to dungeon or anything even if the system decides and required from him even if that strongest person's duty. To be honest, MC have done enough to save the world before why he must save once again if he went out hiding after so many years, just bc he saved the world and expected him to fight again.
Just leave this man rest and don't expect somebody to work until they die. Seriously, everyone needs vacation after they went through or served their time.