If he can only remember two programming languages then he wouldn’t stand a chance in today’s dev ops, t-shaped, m-shaped world I’m afraid. Imagine asking him to help setup an CI pipeline, or some infrastructure but he’s worried learning a bit of Terraform will make him forget his second last language. You just can’t be like that these days. You have to be a jack of all trades and a master of all trades. That’s just where we are and it’s not going to change anytime soon.