When you're a couple of months in, you will probably no longer have to take orders from an idiot that wants you to copy and paste code.
I've been in this situation. The existing developer was stuck in his ways, used a very old-fashioned way of dealing with the language in question and told me to do things that go against every good practice. It was frustrating.
I just agreed, then slowly started asking token advice (for example naming, coding style, things that don't matter to me). Then simultaneously and without asking, I started setting up a git repo, a basic architecture, build server, linter et cetera.
Hang in there, and build their confidence in you. Then slowly you can start doing things your way.