What does the fortune-telling book mean by "mild but difficult to treat"?

Everyone's fate is not completely balanced, and there are more or less "minor illnesses" in the eight characters, which are caused by imbalance or punishment. There is a saying that "it's not surprising that the sick side is precious, and there is no harm", which means that a little "disease" in the eight characters is good, because if this "disease" or gap is cured or filled, it will make a big fortune and be promoted, "serious illness" will make a big fortune, and "minor illness" will make a small fortune. "Serious illness" is easy to treat, while "minor illness" is difficult to treat. The reason is that "serious illness" means that you can see what is missing in his life at a glance, and you just try to make up for it with what is missing, while "minor illness" is different and difficult to grasp. It's easy to make up more, but it's ineffective. This is the truth that "the disease is mild and difficult to treat".