Do the mentioned signs—pronouncing the Shahada, pointing with the index finger, cold sweat on the forehead, smiling, and light on the face at the time of death—indicate a good ending?

All that you have mentioned regarding your father's passing on Friday, his uttering the Shahada, and the sweat on his forehead, are signs of a good end for him — Allah Almighty willing. It has been narrated in the Hadith (definition): "No Muslim dies on Friday or the night of Friday except that Allah protects him from the trial of the grave," and "Whoever's last words are 'La ilaha illa Allah' (There is no god but Allah), Paradise becomes incumbent for him," and "The death of a believer is from the sweat of his brow."