doddering

Mentally or physically infirm due to old age; senile.

You great fat, blasted, blear-eyed, blundering, thundering, brainless, God-forsaken, doddering, damned fool!

Treat the doddering old fool with sympathy.

A shaking or trembling movement, as of old age.

Now that he was next in line to the minister of state security himself, an 82 year old man whose dodderings Fang graciously covered up to save everyone's face, Fang had a huge problem.