What should I do about my father's refusal to shave my son's hair and give its weight in silver as charity, and to circumcise him on the seventh day, even though I see these as recommended Sunnahs, and he sees them as things invented by Muslims?

Shaving the newborn's hair and donating its weight in silver is recommended according to the majority of jurists. Circumcising the newborn on the seventh day is permissible, but not a Sunnah. Obedience to one's father is obligatory unless it involves disobedience to Allah. Do not prioritize the recommended over the obligatory. If your father is not pleased with shaving your son's head, then do not shave it, and donate the estimated weight of the newborn's hair without shaving it.