my mom is in almost the same position. cash his checks, and hold the cash for the funeral. the feds cannot claim it if it is not in an account, and money in an account does count as assets.
the creditors cannot claim any money that is outside of the establishment. but DO NOT sign anything, not even his medical or doctors visits. your name cannot be on any documentation. the creditors will find your phone number and hassle you for payment, but as long as you are not on any paperwork, they cannot go after you.
I hope this helps. stay tough, this is hard stuff for you to be going through.