My 82 yr. old mother who resides in California will be inheriting 100K. She is on a fixed income and before we do anything with this money, we would like to know how much we should set aside for taxes/fees. Thank you for your assistance

As an heir she has no taxes or fees to be concerned with. There is no inheritance tax ihat heirs have to worry about in CA, and if there are any estate tax due on the estate, the executor is responsible for paying it out of the estate's assets before distributing the remainder to the heirs. So this would not affect her inheritance.