His injuries probably weren't the main reason he had sent us to seize the Chaos Seeds. He likely wanted us to surround and attack the Three Evil Immortals while he snatched the prize amid the chaos. After all, the moment those three evil immortals saw him, they went berserk and attacked him alone. It would have been a miracle if he could get his hands on a Chaos Seed.
But once all of us had a chance to seize the Chaos Seeds, fighting the old monster came with a reward. Money could make even ghosts turn a mill, and that gave everyone a reason to surround the Three Evil Immortals. As for why Divine Lord Hua wasn't interfering with our efforts to stop the world's destruction this time, that was only natural. Destroying the world did him no good whatsoever, whereas the thermal core wouldn't be affected by the Boundary Wall and could shoot straight into the Dao Attainment Heaven without any trouble. By saving the world, I was buying him time. There was no way he would stop me.
In fact, if I failed to save the world, he would undoubtedly help me accomplish it. Of course, I couldn't actually leave saving the world to Divine Lord Hua. I simply couldn't trust him with it.
As for Xia Ruize, Li Poxiao, and the Eastern Emperor, they certainly wouldn't interfere with my efforts either. Their goals were already aligned, so the entire burden of saving the world fell on my shoulders. Naturally, that left me deeply frustrated. But even if I didn't want the fame, I wasn't about to hand it to them. Besides, anyone else who took my place might not be able to do what I could. In the end, saving the world had to fall to me.