Is there any financial assistance available for an only child that is forced to leave work to care for their only living parent?

My fiancé of fifteen years and I are over the road commercial truck drivers that live with my mother in law my fiancé is an only child. We have chosen to apply for FMLA through our work to be able to see to the around the clock care his mother needs due to recent massive stroke. We have just lost both incomes because we have driven a truck for the last twelve years as a team for a company that unfortunately due to the type of freight we hauled it is a Mandatory Team Position. FMLA only secures our employment if at the end of the twelve weeks we are able to return to work and see to it that a company doesn't drop our medical insurance as long as we pay the premiums we were paying when we were employed monthly. We are unsure if at the end of twelve weeks if we are able to return to work as of yet. Is there any financial assistance programs available to help my husband and I financially? Can one of us apply for SSI or anything. Or do we do as so many do and put her in a nursing home because she cannot afford to take care of us financially and we are not financially able to just not work we have our financial obligations. We have been full time care takers for starting the ninth week and the future is scaring me as we have began digging into the little we have in savings and wondering what happens when it's gone. When all you have is going out and nothing coming in you really notice it. Thanks for listening :)