My Dad Is 86. He Has Been Sick With Sinus

My dad is 86. He has been sick with sinus drainage and unstable gait past few days but seemed much better today. Now when I call to say goodnight he is saying weird things-worried that he can't find the machine that holds a brown pill that goes off if it gets wet in his bed. Has had incontinence more lately also. Taking guifennison, benydryl, and decadron. Could that build up in his system causing this?