Thess pages contain information about how to apply for a residence permit if your other relative than a spouse, child or guardian is in Finland and is a Finnish citizen or has been granted asylum or a residence permit on the basis of subsidiary protection or temporary protection:
Persons who can be considered other relatives include, for example, the following:
For example, the parents of a spouse or any other relatives of a spouse are not considered to be other relatives of the person living in Finland.
You can also watch our webinar on applying for a residence permit on the basis of family ties (youtube.com). The topics covered in the webinar include residence permit applications, income requirement and extended permits.