If your fiance has health insurance through an employer, that insurance would be his primary payer even if he gets Medicare. If his insurance is an individual plan, it would not be obligated to pay first. Once you get married, if your health insurance is through your work, your insurance would pay before Medicare. If he wants/needs Medicare on the earliest date possible, he should begin a home training program before the first day of his 3rd month of dialysis. Doing this would give him the option to have Medicare start the first day of the month dialysis started. When a patient has Medicare, it limits how much the dialysis clinic can bill. Dialysis clinics typically bill employer group health plan payers more than Medicare allows. If the employer group health plan pays at least what Medicare allows, then it cannot bill your fiance at all.
It's not surprising that being new to in-center dialysis, he doesn't feel like he can work. The recuperation time after a standard in-center hemodialysis treatment is about 7 hours. Most working patients ask for a dialysis shift after work and on days that keep them from having to take any more time off than necessary. Others take a leave of absence. If your fiance works for an employer with 50 or more full or part time employees, he may want to talk with his employer about taking a leave protected by the Family and Medical Leave Act. The leave can be up to 12 weeks/year in increments as small as the shortest amount of time the employer tracks time off. If he's not eligible for this leave, your state may have laws that protect workers in situations like this. The reason why I want to tell you about the option of working vs. the option of Social Security Disability Insurance is that patients ofen do better physically, emotionally, socially, and financially when they keep their jobs.
He can apply for Social Security Disability Insurance (SSDI) through the Social Security office. There is a 5 month waiting period for SSDI but because SSDI pays for the prior month, it takes 6 months to get SSDI. If someone has limited income and assets, Supplemental Security Income (SSI) can pay during that waiting period. The amount that he could make from SSI is $674/mo. How much he'd get from SSDI depends on how much he paid into the program. The Social Security office can tell him how much he'd make or he may have the statement he received from Social Security last year. There are work incentive programs to help patients receiving sSDI return to work. However, he may find it easier in the long run to keep the job he has where his employer knows him to be a good worker. Hopefully his dialysis clinic will help him feel well enough to do all that he wants and needs to do, including starting a new life with you.