For a man, which is better== internal medicine doctor or family practice doctor?

Neither. Both specialties have the training to take excellent care of a man's general health.
Either. Depends. . Rather than whether a doctor is family practitioner or an internist, what is more important is that you find a physician with whom you can connect and develop a trusting professional relationship so that you won't hesitate to share any health concern or ask any question . Good luck.
Family practice . Either one would be good for you. They can treat most disease and illness. But can refer you when needed to a specialist.
Depends. Depends on age and complexity of your illnesses and medication regime. A good internist is worth their weight in penicillin.