I have a 23 year old son who in 2019 was a full time college student. With the stimulus package is it better for him to claim himself for stimulus relief?

It is better for him to claim himself, purely from the point of view of the stimulus payment, but there are other considerations.

If he claims himself, he will receive the stimulus payment of $1200, assuming he qualifies for it. 

If you claim him as a dependent, he will not receive the $1200 payment and you will not get any additional amounts with your stimulus payment.

The other factor to consider is his scholarships, tuition and educational expenses. If he claims himself, he is the only one who can claim his education expenses for a deduction or credit. He may not have enough income to take advantage of the tax benefits.