Can I get my dad an Apple Watch to monitor his heart rate and a fib with out an Apple phone but he does have an iPad and a i Mac ?

Apple Watch is designed to work only with a paired iPhone. Unfortunately your plan will not work, because iPad and iMac have no support or awareness for Apple Watch.

Please also see Track your AFib History with Apple Watch - Apple Support for a few more details. You will see that the display and effective saving of heart data requires an iPhone. This has to be a dedicated iPhone, AFib and other cardiac monitoring are not supported in Family Setup.

Raicya wrote:

Please check if this helps ⤵️

Set up Apple Watch for a family member

Set up Apple Watch for a family member - Apple Support

Set up a family member’s Apple Watch

Set up a family member’s Apple Watch – Apple Support (UK)

Unfortunately the Family Share setup document has a clear list of exclusions which includes the cardiac functions of interest to the OP.

The following features and apps are not available: Medications, respiratory rate, irregular heart rhythm notifications, ECG, AFib History, Cycle Tracking, Sleep, Wrist Temperature, Blood Oxygen, Walking Steadiness, Audiobooks, Remote, News, and Shortcuts.

Please check if this helps ⤵️

Set up Apple Watch for a family member

Set up Apple Watch for a family member - Apple Support

Set up a family member’s Apple Watch

Set up a family member’s Apple Watch – Apple Support (UK)