It seems that type of endoscopy procedure your Dad underwent was a colonoscopy? If so, unfortunately, perforation of the large intestine is a recognized risk of a colonoscopy and is not typically grounds for a malpractice suit in and of itself. Your post does not indicate how much time elapsed from the time of the endoscopy until the time your father had a major operation; however, if there was any delay in recognizing the injury to the large intestine, that might be a basis to pursue a case....
Its hard to know the reason for your first miscarriage. Miscarriages often happen for natural reasons, and, as a result, doctor's often are not required to investigate the reason for the miscarriage. This assumes there were no other abormalities with the preganancy up to the date of the miscarriage. Similarly, its hard to know whether your second miscarriage was caused by the same thing that caused the first miscarriage. Fortunately, your second pregancy was a healthy one, and, so, doctor's had...