Short answer: No. In Tivihar, you should not drink coffee.

• What Tivihar allows: only boiled, filtered water, and only in daylight (after sunrise, before sunset). No tea, coffee, milk, juice, or flavored drinks.
• After sunset: nothing at all (this is observed as Chauvihar).
• Digambar and Shvetambar practices both keep the same core rule here: coffee/tea are not permitted in Tivihar.
• Health note: If you have a medical need, take care of health first and consult your guru/elders.

For simple guides on Tivihar and timing of water: