My husband has misplaced his iPhone on a golf course...can I try to "find his phone" from my phone?

Potentially, yes.

Ref:

• Use Find My to find people and devices - Apple Support
• Use Find My iPhone on iCloud.com on your computer - Apple Support
• If your iPhone, iPad or iPod touch is lost or stolen – Apple Support

Please see the following-

If a friend's device is missing

You can help a friend/relative find their device if it's missing AND has Find My [device] turned ON:

1. Open the Find My app.
2. Choose the Me tab.
3. Select Help a Friend.
4. Have your friend ➔ sign in to iCloud with the Apple ID they're signed in with on their missing device.

Axel F.