Hi! I believe I can be of help with this issue.
I can imagine how frustrating and worrisome this situation must be for you. You are clearly a loving and caring mother. And that you have such a good channel of communication with your daughter in law is wonderful and unusual. She is signaling to you that he's depressed. The depression sounds as though there's more than just some chemical imbalance involved. It sounds as though his emotional/psychological/spiritual self is trying to cope with his past and present and is not harmonizing well.
And this is actually the key to my answer to you that you need to consider and think about. Today, if he goes to a doctor, the doctor will want to immediately prescribe an antidepressant to improve the mood chemically. This is relatively cheap and quick and so is the standard procedure. But it does not change the dynamics in the person's life that caused the downward spiral.
This would be best done with a psychologist or psychotherapist. I don't know if his statement is implying that he's a religious person. If so, then there are religious therapists readily available today.
As you can tell, I am trying to recommend a course of action that steers clear of you trying to step in and make things better for him. I think this would have a much better chance of alienating him from you more than even before. He's not ready to see the relationship with you in a healthy perspective. That needs to come in as part of his getting better in therapy rather as the mechanism of his getting better.
Therefore, I would urge you to communicate with him through his wife that you love him and you are looking forward to when he might want to get together for coffee and chat or whatever he might like, you taking them out to dinner, or whatever.
At the same time, you can communicate to your daughter in law my sense of urgency for him to have professional intervention.
Here is the web address for Psychology Today's therapist directory. You can sort by zip codes and when they see someone who seems like he/she might be helpful (they show you a photo of the therapist!) look at the listing and see if they list depression and in the areas they work with and psychodynamic as well as CBT therapies in their orientations. Interview the therapist and make sure his/her values are similar to you and you feel confident and comfortable with him/her.
Good Therapy is a non profit directory. Same idea as the one above:
Here is one of the bigger directories of Christian counselors. In the above directories you can see if they are religious people but here they are certainly going to have that orientation:
Okay, I wish you the very best!
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