To find Music Therapists in Michigan: go to "Michigan Music Therapists" mmtonline.org (complete list, by county)
I checked out their website and the closest to Midland were:
1) MSU Community Music School (CMS) ($31 for 30 min individual session) and it is an hour and 20 min away. But maybe worth the drive once or twice a month? Contact info is: Cindy Edgerton edgerto3@msu.edu (group music therapy was also mentioned under her name) MSU CMS#: 517-355-7661.
2) Eastern Michigan University (Music Therapy Center) trains music therapists and you can get student led sessions on a sliding pay scale (they're overseen by certified therapists/professors). It's 2 hours away.
3) Harmony Garden Music Therapy is also 2 hours away. Website is: hgmusictherapy.com