Help!

Hello friends! I need some advice, living in BC, my girlfriend and I are trying to figure out our finances as we are wanting to try for a kid in the next year or so, and we have an issue with my girlfriends past taxes, it’s been roughly 6 years since she’s done her taxes as she has been working a cash job under the table for her mother, she’s made less then 12k every year and is technically an “independent contractor” but she never gets t4s and has no way of filing her missing years as she has no way to confirm her income. We are hoping to get this figured out so that we can get our passports and also get access to the baby bonus when we do have kids, we have already decided that once we’re pregnant she’ll be taking a more stay at home position, so we’re not worried about future taxes, just need to know our options as to get her squared with the CRA for the back taxes, any help would be greatly appreciated