You may evict a tenant who is in jail if they have not paid rent or made arrangements to pay rent. The main issue here is whether or not rent was paid, not necessarily what their current life situation is right now. One thing to bear in mind is that the unauthorized tenant may also require proper notice in any unlawful detainer proceedings. Make sure to include them in the caption on all paperwork since you know they exist, and it does not hurt to provide them with their own copy of the summons and complaint.
Hiring an attorney for these matters is always recommended.
This answer is for informational purposes only and should not be construed to establish an attorney client relationship. Before taking any legal action, it is always advisable to discuss your specific situation with an attorney.