Change of Visa from F1 to H1B

[SCV]

I have a client who was on F1B from Jan 1 to Sept 30, 2019 and changed visa to H1B from Oct 1, 2019. He was out of the US for 40 days in Nov-Dec 2019 and so cannot meet First year Choice of Residency Requirement. When filing as Non Resident - 1040 NR, can he still claim standard deduction under Article 21(2) of US - India Income Tax Treaty. If not for the entire year, is there a way to claim the treaty benefits from Jan - September by filing some kind of dual status return.