TLDR: I feel like my boss is trying to learn my skills so he can throw me away and do everything by himself. How do I make sure that I'm not being taken advantage of?
I'll try to keep this short. I am not exactly an employee of a company. Rather, I have this friend (or boss) who designs websites and then I convert the design into an actual working website. I then get payed a fixed amount every month. There are no job contracts, it's a purely personal transaction.
Disregarding the pay which is quite smaller than I want it to be (around US$ 5,300 yearly) for my job description (which is not limited to web development, and includes server administration, full stack software development, language translation, among others), he's an understanding person and while nothing is perfect, it's good working with him.
Suddenly, I learned that now he's learning the basics of what I am doing for him. Now he's learning JavaScript, CSS, Git, computer hardware, stuff that he was clueless about before. He even asks me questions and I have to solve problems he encounter while learning by himself, explain things to him, teach him things when he can't understand the stuff he reads on the internet (there's a possibility that he's taking some online class since he sometimes makes me answer some Google Forms quiz stuff about my expertise), something I am not exactly willing to do since I'm a developer, not a teacher. But he's a friend, and my boss, so I don't exactly decline.
I am afraid that he's trying to learn my skills so once he can design and build websites by himself, he'll just throw me away… like, I understand that software engineering is basically something that you study for a very long amount of time and takes tons of effort to be actually good at it, but… I can't help but feel resentment and sometimes, worry.
What could be the best course of action to make sure that I am not being taken advantage of? Thank you in advance to everyone.