We don't know what made Jeremy leave the company and how he helped before YC.
If this is a case Jeremy was present at incorporation, he contributed to the product (in some way) and his shares were eventually diluted, this will be similar to Saverin's case.
If this is a case Jeremy was present at incorporation, he contributed to the product (in some way) and his shares were eventually diluted, this will be similar to Saverin's case.