That's dicey. Raise the price on his patterns and give you the ones he bought.
To me each individual purchased pattern comes with its own standards to the law depending on the restrictions imposed by the designer. As an example: One site states:
All patterns are fully covered by US Copyright Laws and are intended for end use by hobbyists and craftsmen only, and may not be distributed, made available, published or sold for any commercial purpose as patterns, or designs.
IM don't know opinion. Take the patterns, don't sell what you make from them.