My father, who is 65, is dying of ALS or: lou gherigs disease. How painful will his death be? And what are the signs hes getting close to dying?

So sorry. ALS is a nasty disease, and many pts have pain, but this can easily be controlled with analgesics, and strong opioids would not be inappropriate. Most pts die from infection, such as pneumonia, so, a fever and trouble breathing might be a sign of problems. Usually, toward the end, a hospice is marvelous for palliation, emotional support, and understanding.