Emergency fund is needed only after starting investment, that is why emergency fund is needed where you can continue investing Bitcoin regularly on a weekly basis. Investing Bitcoin according to the DCA method will allow you to buy Bitcoin regularly and you will also be able to hold it for a long time.
If you spend time in illness, then you may refrain from investing because you may not have money saved, then you can invest Bitcoin from emergency fund. Regular DCA method will be followed to deal with danger and to sustain Bitcoin investment for a long time.
Whether you invest or not, you need to have an emergency fund. You never know when you will have a financial crisis. You never know when you will fall into the middle of a financial disaster, so it is necessary to have an emergency fund to deal with this financial disaster.
DCA method is an investment method through which you can buy Bitcoin at any time at any price. DCA method never helps you to hold your holdings long-term. Holding it long-term depends entirely on you.
It is never right to invest with emergency funds. If you get sick and do not have money to invest, then you can stop investing for a few days, but it is not right to invest with emergency funds. Emergency funds are not always right to take money, when you do not have any money other than emergency funds, you can use emergency funds if you want.