Tell father first, then decide
He does not know about the offer, and you have not asked his wishes. Speaking first replaces assumed worry with what he actually says, and opens room to raise your sister.
If you do this: You learn whether his attachment is to the business continuing or to you running it. He may be hurt or surprised; you decide on facts, with January still ahead.
Cost: An uncomfortable conversation, possible disappointment voiced aloud, some days of waiting.
You: Choose a quiet time this week and tell your father about the Pune offer in person.
The exact first sentence“Papa, I have been offered a job in Pune, and before I decide anything I want to hear what you would want for the business.”