Q. If a sentence contains a compound subject in which one of the subjects is dead while the other is alive, is the verb written in the present or past tense?
A. It depends. If the action clearly takes place in the present, use the present (Aristotle and Susie Jones are examples in this answer); if it clearly took place in the past, use the past (Abe Lincoln and Susie Jones were both born in Kentucky). If the “historic present” is more appropriate, that’s another choice (Aristotle and Susie Jones both write about logic). If you meet with difficulties (Both Lincoln and Jones are/were tall?), recast the sentence to minimize the problem (Like Lincoln, Jones is tall).