For some reason I can't write an answer to the commentator, the page disappears and I have to reload the tab. Therefore, I will write an answer with a separate comment.
Yes, it's difficult with him. I found such a tactic for myself. Firstly, after receiving the gun, do not use it, so as not to waste cartridges. Inspect every corner of the location in search of additional cartridges. When fighting a boss, come close to him to trigger an attack animation and quickly move back. While he's attacking, shoot him with a pistol. In the second stage of the boss, try to kill simple zombies with a stick first, so as not to waste ammo on them. Then start triggering the boss to attack, just approach him and move away. During the animation of the attack, shoot him in the head with a pistol, try to hit the red sphere. This is his weak point and so you do more damage to him. When the boss falls, approach him and hit him with a stick until the stamina runs out. I don't know if it makes sense to hit the head, it seemed to me that when hitting the head and the body, the damage is the same. An important tip, DO NOT reload your weapon if there are still cartridges left in the store. They will not return to the total account, but will simply disappear. And you will lose valuable ammunition