Holy shit, you are going to have fun staying poor if you believe that you need to hold 2 years of cash for expenses merely because you have a family of 6 persons in which you are responsible.
If you have a family of 6, then your expenses per month are already likely going to be higher than a single person, yet several of the costs are going to be shared, so with some costs you are not adding equal amounts for each extra person.
I will agree that you will likely have extra expenses and needs for greater emergency funds and reserve funds, yet it likely not going to be any where near the levels that you are calculating to change your minimal requirement for 3 months of emergency funds to 18 (6x) months of emergency funds.. that is completely ridiculous and out of touch with reality or logical.
In the end, each of us needs to choose how much to invest into bitcoin versus how much of various back up funds that we might keep based on our expenses and/or based on our expectations that we might experience shortages in our discretionary funds due to lessening of our income and/or increases in our expenses.
Like you said, it is the dumbest idea, and one who does that must have no clue about "what is inflation?"
I would recommend 3-6 months of cash as maximum and anything beyond is just wasting the potential money making opportunity and one who doesn't want to take any risks can go with the gold that is most likely not going to fall no matter what and if they want something that's from government then bonds can be an option even though these all are no where near with the returns offered by bitcoin but just in case they want to be safe and no risk at all. But like the classic saying, 'No risk No reward' so good luck them stay stuck where they are currently.
And one thing I noticed with most users here or in general not to make use of the health insurance and that is likely going to be most emergency we can stumble on all of a sudden that can be tackled with right insurance package depends on our needs and life insurance in case of unfortunate events so the family can survive from the money for a while and think about their next plan in our absense.
Summary: Don't keep as cash that you will need for no more than 3 months, buy the health insurance, prepare the retirement plan as early as possible and start investing based on our risk tolerance.