...cannot predict with any accuracy what will befall any one individual.
Just a quibble, but I don't think we should accept a blanket statement that biology or medicine can't predict what will happen to an individual. We do understand the mechanics about enough processes to know what will happen to certain people, such as those people with various genetic defects, such as for Huntington's disease.
Somebody with medical credentials should step in to lead us through this maze. However, I seem to have accumulated information that the progress of any one person's disease is highly variable and unpredictable.
Actually, the fact is that biology/medicine encompasses elements of "hard" science and "soft" science depending on the particular field or the question, so it's not so easy to give it a single label. Look at Watson and Crick, the discoverers of the structure of DNA. Using x-ray crystallography to tease out its structure is pretty "hard science".
First, let recall that it was Rosalind Franklin who was the x-ray crystallographer, not Watson or Crick. It was only the no-postumous-Nobel rule that deprived her of that recognition for her DNA work. She went on to a distinguished career perhaps capped by her on Nobel prize for other contributions to science.
Second, you are right that there are aspects of science, hard, soft, or otherwise that permeate or invade their theoretical opposites.