How to treat an under-performing coauthor?
You might simply consider that the current situation is fine: you say that you do get help from your collaborator, so there is little reason to stop working with him or her; you lead the collaboration and, for this, get first authorship. This will earn you much (well deserved) better opportunities; by comparison, your collaborator will have a hard time, because no recent first-author publications will look bad on his or her CV.

You might have wanted a more active collaborator, and it is a good idea to try to help him or her do better, but you just cannot push someone against their will. It is possible that he or she does not have what it takes to handle more core tasks, or that so he or she believes. In this case, pushing too hard would amount to cornering him or her into an impossible situation, no good would happen.

Learn to change what you can (e.g., if you have the option to start another collaboration with someone else it might be a very good idea; if you have another job available with potentially better co-worker, you might want to try it, etc.) and do with what you cannot change. Ultimately, you have the upper hand on your own work, and that is how it is supposed to be.

Ho, and about getting co-authorship in exchange for your work: no one is supposed to give you co-authorship in exchange for anything; you can rather be invited to work on a project, and then this work is what grants co-authorship. I am not sure how you meant it, but giving co-authorship as a mere reward for something unrelated to the publication is a serious academic misconduct.