@angiede2001, This must be hard for you to witness. But as having been a patient, I will try to add some input based on my experiences and I am by no means informed on dialysis.
I needed dialysis in an emergency situation, and I was quite unaware of what was going on. But, when I needed to have a more permanent port put in I was more alert and in a regular hospital setting. I was absolutely terrified of having 'that thing' placed inside of my body. The mere thought of it happening made me nauseous. But it happened anyway. After that, I dealt with the thought of my own blood going thru the machine, another agony in my mind. I share this, because this might be some of what is going on inside your husband's mind. These thoughts are something that my husband didn't really understand. From his point of view, he just saw it as a doing what was needed to get me well.
Perhaps, your husband just needs time to process this concept. And perhaps, he is stressing about his condition moving beyond his control. I think that the medical team might be the best ones to do the 'dirty work' to educate him on this. You can help by supporting and calmly discussing this with him, and especially letting him know that you love him and will be with him.
There are a lot of people who are able to continue active lives while undergoing dialysis. You might ask if there is someone that your husband can talk to.
Rosemary