Hi, so sorry to hear what you and your husband are going through.
I can tell you how I've dealt with my own, sometimes severe, depression and suicidal thoughts (some of which have lead to suicide attempts).
I've had depression since my teenage years.
I've hit 'rock bottom' many times when I've wanted to end my life, sometimes just thoughts of ending my life and sometimes attempts to end my life.
I found my family very unhelpful and of the belief I'm just 'attention seeking' and there seems to be a general mistaken belief that if you talk about taking your life, you would never do it...anyone that does really want to, keeps it secret
.
My partner seemed concerned about me, but still didn't seem to take it seriously...broke the bathroom door down to stop my slitting my wrists, pulled the blades off me, but then left them laying around and didn't bring up the whole incident again
I self referred earlier this year to NHS self referral after bad depression & strong suicidal urges, they put me on a CBT waiting list and said it would be at least 6 months to wait (I didn't go through my doctor as had previously gone through my doctor asking to have CBT and was told I could only go on the waiting list if I took AD prescription first, which I refused as I didn't want the AD side effects)...they offered me no other help, despite me saying in a telephone interview I was suicidal.
I paid £50/week to go to a private 'EMDR' therapist for 4 weeks who never actually got round to doing any EMDR!! 
I contacted a local CBT therapist who advertised that she had a student of CBT who charged less for sessions...explained I'm on the minimum wage, could I have some appointments with her student...she replied saying sorry, she couldn't help me????!!!! (great empathy skills for a therapist!!)
Sooooooo, coming to the conclusion that I might have only myself to rely on (not easy when you are depressed!!)...I got out my CBT self help books out and forced myself everyday to do the exercises. I've done the self help before and it's great, but you really need to keep at it and keep at it probably for the rest of your life, because the illogical thoughts keep coming back.
Light bulb moment came for me when reading about how the author of the books treated a suicidal woman who had previously been in an abusive relationship...she and author worked out she'd been telling herself she was 'defective' and believed that's why she'd been abused...so basically blaming herself for the abuse.
This rang bells for me and I knew I was telling myself the same thing (alongside other illogical beliefs, such as expecting myself to be perfect, everyone to like me etc etc!), I'd been on the end of bullying abusive behaviour from family and work colleagues.
I did the exercises to deal with these thoughts..particularly helpful was 'Acceptance Paradox'...most powerful CBT technique I've used.
I had a complete turnaround and my depression lifted and suicidal thoughts went.
I make time every week, every other day is best, to do the exercises and the depression scales (depression score sheet) before and after to see if the exercises are working...it always works! 
The books are by Dr David Burns... 'Feeling Good the New Mood Therapy', '10 Days to Self Esteem' and 'When Panic Attacks' are the ones I use the most. I keep a notebook for the exercises.
This last 6 months is the best I've felt nearly the whole of my life.
Maybe these books could help your husband? I follow the author's blog and he said how pleased he was to receive a letter from someone who had decided to end their life, until a friend gave them his book 'Feeling Good' and it stopped him and changed his life.