My husband is burned out with caregiving for MIL. Any advice?

Four years of difficulties. Frustration level has peaked - my husband is burned out and just can't get his peace of mind back. My 84 year old mother with macula degeneration and borderline dementia has gone too far. He can't stand to SEE her now - needs a break - but for the long hall who can we consult to help us work through this anger and learn coping skills for caregiving? My mother resists every and any requests for her safety or our cat's. It is a 4-5 hour beseeching, conjoling, begging episode for her to use her cane, chair lift, rollator, not over feed our pre-diabetic cat (per the vet). She continues to sneak around walking up the stairs when we're in bed, hiding food for cat in closets to go back to, not using her cane outside to walk, not using tops of cups - she has macula degeneration and is shakey and spills or breaks everything she touches. We have gotten EVERYTHING she needs and will continue to but now it's my HUS BAND who is having problems - he is simply sick of this and burned out. We are getting help through agencies and have just begun the search but would like to know the best approach for caregivers? He is searching for work and doesn't want a psychiatrist on his record cause of the stigma - is there a good professional approach or 'counselor' we could contact? We have name of coping group that meets, We are having her retested - she was borderline dementia a few years ago - she is OBSTINATE - lies, sneaks to do whatever she wants to REGARDLESS of who she would hurt. This is not my mother and I can't keep apologizing enough - after a while it just doesn't matter - you get into survival mode. We are having a life coach come, we have talked to our minister - but we need some real information to move forward. At this point I'm more concerned about my HUSBAND who has had double knee replacement and a blood disorder treating for 1 1/2 years...I've had gall bladder surgery, shoulder surgery, have chronic IBS and now had heart ablation (I think it's the stress). She has fallen 7 times - in situations where I have continually asked her not to do something (i.e., take bags out of the car - I say 'just get yourself in the house safely') She grabbed bags around the other side of the car and then fell FLAT on her face on the sidewalk. She HATES her chair lift because it beeps and wants to 'sneak' down to overfeed the cat - we have spent HOURS and HOURS telling her to use the chair and my husband ever called in he repairman to TELL HER (cause she won't listen to us). When she has a gastro attack (in teh kitchen all over shoes, pants floor - we asked if she's OK - we smelled it but she doesn't smell anymore - and she says, 'yes I'm fine - nothing's wrong'. My husband says 'it's a matter of the safety and cleanliness of everyone in this house you need to be HONEST with us'. We have talked about this for years now - she cries and says it's embarrassing - she has feces on her SHOE and didn't even know it when I went into the kitchen she still tried to lie to my face!!!!! I am dumbfounded at her obstinance. She ONLY does things out of ANGER and SPITE. She went with the rollator out back which my mason husband has totally turned into a beautiful and safe senior walking area - yet TOOK OFF to the Dollar Store without telling us. We hopped in the car and tracked her for 2 hours so she could have her walk cause she's a couch potato. I had surgery and she wasn't getting 100% attention. She has hit my husband saying he has me hostage in our room when I was recovering. He has been taking care of her and me for 2 months since my surgery - she doesn't have to lift a finger. She is spoiled and has always had everything she wants since my Dad died early (54) I have lived with her and/or taken care of her. My husband and I married late in our 40's and I think she's jealous of him and it is a terrible emotion. She is a minister's wife and my husband says he can no longer respect her with this behavior. She has put her hand on the Bible saying she will change crying and sobbing and doesn't change anything ever. Thanks for all who can share what HELP they have identified that has been successful.