Here's how you could respond, depending on the situation:
1. If you know Tomas' schedule:
* "Tomas tiene clases de [Monday] a [Friday]." (Tomas has classes from Monday to Friday)
* "Tomas tiene clases los [list specific days of the week]." (Tomas has classes on [list specific days of the week])
* "Tomas tiene clases [specific days] y [specific days]." (Tomas has classes [specific days] and [specific days])
2. If you don't know Tomas' schedule:
* "No lo sé. ¿Por qué no le preguntas a Tomas?" (I don't know. Why don't you ask Tomas?)
* "No estoy seguro. Puede que tengas que preguntarle a él." (I'm not sure. You might have to ask him)
3. If you want to be more casual:
* "No tengo ni idea. ¿Tú sabes?" (I have no idea. Do you know?)
* "No sé, pero podrías preguntarle." (I don't know, but you could ask him.)
Remember to use the correct conjugation of the verb "tener" (to have) based on the subject "Tomas."