It looks like you want a pivot report, not a chart.
To do that you're probably looking at creating a virtual list report:
The script to gather your data would probably look something like:
-Get a list of unique dates from the two child tables for the patient.
-Sort the list of unique dates.
-Gather columns of data for each unique date.
-Display the data in the virtual report.
Unfortunately, you will always be limited in the format you want since the number of columns is limited to the number of fields you setup. It might be more ideal to pivot it, so each date is a row, and you have your Hb, TC of WBC, etc... as your columns. That way you could support a patient's entire history.
Kindly can you post demo file or example script for better understanding. Thnx in advance.
The blog post I linked to has an introduction, and a google search for "filemaker virtual lists" turns up a number of blogs and videos.
If you need a developer to do the work for you, or mentor you through it, I can point you towards mentoring, training or consultant services.