Student or Learner
I have always seen "all I know is, all I have is" used in the language.
Context: "All I have is my Mom" I know this is correct. It's because maybe there is only one object(Mom). What about if there more than one object? For examples: All I have is/are my Mom and Dad. What should I use? Is or are?
You can avoid the issue by switching the order:
My Mom and Dad are all I have.