airdrop

Let's start by verifying that your iOS devices meet the minimum requirements for using AirDrop:

To AirDrop pictures and videos between iOS devices, you need:

• An iPhone 5 or later
• iPad Pro
• An iPad (4th generation or later)
• An iPad mini or later
• An iPod touch (5th generation or later)
• iOS 7+
• Both devices need to have Bluetooth (4.0 LE) & Wi-Fi enabled.

It looks like both your iPad Air 2 and iPhone 6s should meet these.

Take a look at this iDownloadBlog Support article to start troubleshooting. You may also find this TechRepublic article helpful as well.

Please post back your results.

His devices meet the iOS requirements but not sure if his computer does:

AirDrop system requirements

To send items to an iPhone, iPad, or iPod touch, or to receive items from those devices, you need a 2012 or later Mac model with OS X Yosemite or later, excluding the Mac Pro (Mid 2012).

Use AirDrop to send content from your Mac - Apple Support