If an investor is strictly investing in bitcoin with his discretionary income, he is free to invest in bitcoin with all his discretionary income if he chooses to do that,
No, I don't think it's a good idea to invest all of your discretionary income because their are so many things we spend money on that are not part of our basic needs, but are very important, so like 60% is ok, anything more than that might put you into a difficult state in sorting out those expense that is not part of our basic needs.
Any financial crisis that happens after you have paid for your monthly expenses should be treated as an emergency because you don't plan for it,
No I disagree with this statement here, when we are talking of emergencies, we are talking about real life emergency situation that threatens your holdings, not minor expenses that can be sorted out with our reserves funds or a fraction of our discretionary income, that's why it's not good to invest with all your discretionary income so that you wouldn't have to act in such a manner at a point.