What should I do if my former advisor wants to use my research project data (including dissertation) for the current PhD student's dissertation? I finished my dissertation about 2 years ago and currently continue for a clinical program in the same department. I collected the data from many subjects for my research project including dissertation while doing my PhD and all subjects and experimental supplies were paid from my own pocket. I am now preparing for publications. Because I am now taking a pretty demanding professional program, the writing process is pretty slow and all manuscripts are still in progress. I think that it will probably take some time to publish all of them. For this reason, I am a little bit cautious about sharing the data with someone who wants to write their dissertation using my data.
My former advisor and their current PhD student decided to use the pre-existing data for the dissertation and the student asked me for my research data including the dissertation. Even though the research question will be different and some survey data will be added (the subjects who participated in my research may need to be contacted), basically my data would work as the main data for the new dissertation in consideration of research in this field.
Additionally, my former advisor does not know about my data and whenever the PhD student has questions and needs some help with data interpretation, I am pretty sure that they will ask me for help. I will leave the school next summer and it is not easy to work with them in a remote location especially because I will be working full time. I am not sure if this is conventional and a general case. I like to get some advice so I can figure out how to deal with this.
It would be good if you can find a way for this to work to everyone's benefit.
I'd suggest that you start with your advisor and express your concerns and get some assurance that the other student won't be stepping on your research. You should be able to get a great acknowledgement in work of the other student. And your own work might well be eligible for citation under these circumstances.
But also express your need for the time for your own work and that  you can't prioritize helping the other student at this time.
Once you have some agreement from  your advisor, initiate a three way conversation in which everything is made clear. You'll help when can, but have other priorities that must come first. But from your description, it sounds like it is possible for everyone to win as long as the others respect your limits.