Can I ask what they are doing for you? I mean, I dont need specific details, but is this a few hours of work or a larger project?
Sometimes people are struggling with their own life, depression, anxiety etc that makes it nearly impossible to get certain things done. You can have compassion for those people, and do what you can to help, but there can be a point when it is interfering with your own life struggles. If that is the case, you can still have compassion and empathy for them, but for your own sake you have to let them know that you cannot wait forever, and if they cant complete whatever the project is, you understand that. However, you have to let them know that you need to get the project done and will have to look elsewhere for getting it done.
Good luck.