Welcome to PC!
You are in a tough spot.
I also experience treatment-resistant depression.
While I have needed understanding, I have also found I do well with some occasional prodding from my husband. While treatment-resistant depression can be "reality," so is taking care financially. As you are currently one another's life partners, you (realistically) have a duty to be accountable toward one another.
You are right on, in that anyone with treatment-resistant depression cannot afford to wait on meds only. I feel learning coping strategies is a very helpful/healthy option. I hope he will agree to pursue help.
If he cannot pursue treatment avenues for himself, hopefully he can for you/your relationship. As noted above, you may, at some point, have to draw a line in the sand. A couples counselor might be very helpful to you.
I feel he has an obligation to himself and to you -- to try all reasonable and available treatment options. Learning coping skills and engaging in therapy can be very helpful.
Please understand that I also suffer from some very, very long bouts of paralyzing depression. I try many things that might be helpful -- when I cannot do it for myself (because I am too depressed)-- I recall my vows and my duty to be as much of a life partner as is truly possible toward my husband.
My husband also has a mental health issue which can cause severe depression. We show one another great support, patience and... mutual accountability.
While your hubby needs care, compassion and understanding, he may also need some kind of a wake-up call if her persists in not seeking out further assistance.
I hope things work out!

WC