You don't have to be a linguist or a language teacher to support someone else in her or his language learning. The most important thing is to be sensitive to the learner's needs, and for how comfortable you are with eachother. There is a differences between wanting to be corrected, and wanted to be understood.
One way of supporting a language learner is to simply do things together, naming what is happening and what is needed in the situation. You can do this in physical or digital worlds. If you'd like to just sit down and talk, it's often a good idea to have something concrete to focus on, like a picture, a song or an news paper article.
The tips we have mentioned for language learners in these pages, can guide you to become a successsful language learner supporter. There are also some good advice if you search the web. Good luck!
/Christine Ericsdotter Nordgren, August 2016. Translation: Albin Hillert