Air India typically releases partner award space for just a single business class seat and a single first class seat. Air India has been very generous with releasing the specifically mentioned (1 seat each) award space for the entire year (see image below for summer 2024).
Availability to book 11 months ahead of time is also very generous (see Seats.aero.com availability image below for January 2025).
Best way to book two premium cabin seats to travel to India
If you are looking for two premium cabin seats to travel to Delhi, I recommend booking a single available business class seat for one person and a first class seat for the other. You may not sit next to each other, but it would be comfortable to lay flat and travel to India for 14 hours.
LifeMiles
Using LifeMiles will save you 10K points for the first class (see image below).
Aeroplan
Aeroplan will charge the same miles for business class, but charges 10K more for first class bookings.
Conclusion
I suggested this option to two of my friends traveling to India and they immediately utilized the opportunity to book the seats. It is difficult to find award space for two business class seats when traveling to India. Air India has recently upgraded their A350-900 cabins and received positive reviews.