My father underwent a craniotomy 12.15.14 and has been making remarkable recovery. tonight he got very tired started slurring his words. temp 98.9?

Nearest ER: it is difficult to answer your question. Without knowing the reasons he underwent a craniotomy. Although it has been a while since his operation he is still at risk for developing complication and not mention a possibility of TIA or stroke. Alternatively a seizure is also a possibility but all these would depend on the various scenarios and throughout exam. Please seek medical attention Asap