come the old soldier
To attempt to mislead someone or avoid doing something by using one's age as an excuse. Oh, Grandpa, I know you're strong enough to help move these boxes—don't come the old soldier with me!
come (or play) the old soldier
use your greater age or experience of life to deceive someone or to shirk a duty. informal In US nautical slang a soldier or an old soldier was an incompetent seaman.