DC is a strategy that can be run and we do not need large capital during consistency to do regularly, Bitcoin can increase slowly. Regarding the need for money and does not need to sell bitcoin it can be adjusted, therefore we do not need to invest all the money possessed and can be made percentage so as not to affect the investment we are living.
Yes even though the DCA is good for everyone to invest, the investor will need constant income probably weekly or monthly if not even the DCA can't be effective for the investor. Because the person is using that method because he does not have enough funds to invest at once so what has to do is to look into his income and plan to invest according to the income. And as you said there must be a persistent top up of the DCA to increase the portfolio.
Invest what you can afford to survive and not all the money at once. You can divide the income into two and use one part for the investment and the other part to do things in the family to avoid quarreling. Invest wise.