Kale is slang for money, it's not just cabbage, which is also slang for money, so you can't have your money and spend it too. It's my updated version of the idiom, " you can't have your cake and eat it too".
Put your money in a safe place son, because you can't have your kale and spend it too.
When some resigns or retires from a job, they are on "eternity leave". This can also refer to someone who has passed away, especially someone who worked somewhere for a long time, retired/resigned, then passed away later.
Oh I'm sorry, you didn't know that Kelly is on eternity leave? She resigned and moved to Hawaii!
With regrets I would like to inform you that my boss is officially on eternity leave. I will never see or hear them again. Ever.