He's not masturbating but he stiffens his back and panting heavily. he has Alzheimer's is takes his meds daily, could he possibly have an infection or is this normal behavior? He doesn't speak improperly to myself or others and caretaker hasn't said anything about his behavior.
Why would you think he's having mental sex?
This is nothing to be messed with, see the doctor right away. Never attempt to abruptly stop a psychiatric medication, or withdraw from the drug without a doctor's supervision.
This may become a life threatening symptom.
Sorry, please don't shoot the messenger. You were right to ask the question.
Just trying to cover all the bases here, and apologize in advance for mentioning this: Could it be a sign of withdrawal from a medication? Some caregivers steal the meds.
"mind only" sex, especially since he is not masturbating nor is he inappropriate in speech with either you or others.