There are therapists who specialize in grief, but most therapists recognize that grief can cause depression. (A mentally healthy person is miserable after the death of someone they love. They only consider it "depression" if the awful part lasts a long time.)

The LW is in Massachusetts, so they have health insurance that includes mental health care. They don't need to tell their primary care doctor who they're grieving for--just that they're depressed, and have been since their sweetheart died more than 2 years ago. If therapists are organizing a support group, they can check that the LW and the widow aren't in the same one. ("Can you make sure my mom isn't in the group, before I go talk about dad's death?" "Sure. How do you spell her name?")