Situation is:
A residential home with a detached garage has a sub panel which is
serviced from a 50A breaker located in the main breaker box. This
service feed is approximately 20'.
The house has a meter pan/disconnect where the 200A service enters the
house.
The breaker box is approximately 30' from the meter pan. There is a
grounding rod, earthed at the meter pan entrance which goes to the
breaker panel.
The water lines are bonded.
My main question is should the sub panel in the garage be earthed or do
I use the ground wire from the main to act as my safety ground like to
carry currents from a lightning strike to the original earthed point all
the way across the house by the meter pan.

Since the garage is detached, wouldn't I want to provide a path for
lightning to the closest point?

Any advice will be appreciated. :-)
Thank you