Is it safe to buy a phone off amazon?

Sometimes items are sold by other sellers through Amazon, and the reliability pf those sellers varies. However, the phone your Dad wants is shipped from and sold by Amazon, so it should be safe. I've bought many things from Amazon (not cell phones) and never had any problems. Just make sure to follow the instructions for transferring your Dad's phone number to the new phone. You can call Amazon's "cell phone experts" if you have any questions or need istance.