54 year old with dementia

My husband is 54 years old and a cancer survivor (lymphoma). During his 8 year long battle which included a stem cell transplant and countless hours of chemotherapy, he has contracted what is thought to be Progressive multi-focal leukoencephalopathy. As his dementia has been more and more noticable, I feel the need to ask for some financial counseling. I have always worked full time, but have recently had to cut back to 24 hours a week. My 78 year old mother in law currently is his caregiver while I am at work, but I know that she cannot continue to do so once his behavior becomes more aggressive. My husband receives SSI and has a disability policy with his former employer. His healthcare coverage is Medicare and a medigap plan F. I have contacted various agencies, but am confused as to what my financial situation would be if he needs to go to a skilled nursing facility. We both have small individual pensions and a house with a mortgage.