Does mMedicare cover external catheter for men?

Yes, Medicare Part B covers male external catheters, classifying them as Durable Medical Equipment (DME). For men, Medicare typically covers up to 35 external catheters per month, provided they are deemed medically necessary by a healthcare provider. 
For more information Read: https://medicareabc.com/medicare-coverage-for-purewick/

Medicare and supplemental insurance did pay for dad's catheters. But you have to speak to the prescribing doctor/urologist to get set up with supplies and coaching on how the catheters are to be used, You don't just go to CVS and buy them and figure it all out yourself.....they are medical supplies. Please get advice from the doctor on how to proceed.