how do i stop being depressed over my parents and their lives?

Your parents are adults and can take care of themselves. Decisions they make and things they do they should be responsible for not you. They are responsible for their own happiness, as much as you are responsible for your own.

You can't control their lives and it's more difficult on you if you try. It will stress you out and push you further more down. You can care about their actions but they know what is best for them and you know what is best for you. How would you react I'd they were doing the sanding in your life like you are them? Would you want them to be depressed about your life or have them try to help you and be supportive with whatever they choose. Now it does depend on what it is but it might be better just to post yourself from them and whatever I'd making you depressed about it.