Can an Apple Watch Series 5 be set up with an iPad?

No. The Apple watch requires an iPhone. It will not work with an iPad.

Also, if its a brand new Apple watch running watchOS 6 it will require at least an iPhone 6s running iOS 13.

Apple Holiday Return Policy (Purchase between: 15-Nov-2019 thru 25-Dec-2019, Return by 8-Jan-2020)

Items purchased at the Apple Online Store that are received between November 15, 2019 and December 25, 2019, may be returned through January 8, 2020. Please note that all other terms and conditions provided in the Apple Online Store Sales and Refunds Policy are still applicable with respect to such items purchased. All purchases made before November 15, 2019 and after December 25, 2019, are subject to the Standard 14-day Return Policy. 

https://www.apple.com/shop/help/returns_refund

eejones39 wrote:

I purchased an Apple watch for my husband for xmas. I know it cannot be used with his Iphone 4; can it be set up with his Ipad?

No, iPad is not compatible.

You need to add a newer iPhone 8 or later model to his Xmas list.

You're very welcome.