He is not talking/making sense. Don't listen to him.
Do talking and making amount to each other in the above? Does the first part of the above also refer to "He is not sensible/reasonable?" Thanks.
Yes. "He is not making sense" or (less often) "He is not talking sense" means that what the person is saying is not logical. It means that what the person is saying does not stand the test of reason. It is nonsensical. It is irrational.
Yes. "He is not making sense" or (less often) "He is not talking sense" means that what the person is saying is not logical. It means that what the person is saying does not stand the test of reason. It is nonsensical. It is irrational.