I wouldn't run it during the warranty period. He should just look in his OM.
The OM states:
Engine Oil Selection
For best performance and maximum protection for all
engines under all types of operating conditions, the
manufacturer recommends engine oils that are API Certified
and meet the requirements of Chrysler Material
Standard MS-6395.
Engine Oil Viscosity – 3.6L Engine
SAE 5W-30 engine oil is recommended for all operating
temperatures. This engine oil improves low temperature
starting and vehicle fuel economy.
Engine Oil Viscosity – 5.7L Engine
SAE 5W-20 engine oil is recommended for all operating
temperatures. This engine oil improves low temperature
starting and vehicle fuel economy.
NOTE: Vehicles equipped with a 5.7L engine must use
SAE 5W-20 oil. Failure to do so may result in improper
operation of the Multiple Displacement System (MDS).
Refer to “Multi-Displacement System” in “Starting and
Operating” for further information.
Lubricants, which do not have both the engine oil certification
mark and the correct SAE viscosity grade number,
should not be used.
Synthetic Engine Oils
You may use synthetic engine oils if the recommended oil
quality requirements are met, and the recommended
maintenance intervals for oil and filter changes are
followed.