Apparently a very understanding and cool minded boss.
Apparently a very flakey boss, who as well as being genuinely cool-minded is passing some of that flakiness off as cool-mindedness.
I would hazard a guess that legally your employer is in material breach of contract, even if you don't have any realistic hope of enforcing the contract.
How understanding and cool-minded would they be if you just didn't show up to work for a few days and then wandered in? Don't do that of course (tantrums don't help), but that's about as cool-minded as you need to be about late payment. There is basically no excuse on earth for not paying what you owe and not telling the person you owe it to, on or before the date payment was due, everything you know about the reason for non-payment[*].
You don't need to be grateful to your employer for valuing your ideas -- it's part of what you're paid for, especially as a senior employee. Your ideas benefit your employer. So be glad of it but don't use it as an excuse on their behalf.
You should give credit for the general laxity, if it's unusual and it benefits you, and be somewhat lax in return. But that must be within reasonable limits, don't give them more credit than they're really due. Ultimately you aren't there for the lack of strictness, you're there to earn a living. So, you might well feel that since you value the company it's worth the risk of staying despite unreliable cash flow, and a reasonable chance that some day they'll run out of money entirely and you'll be left a certain amount out of pocket[**]. But you should assess it as a gamble and you should figure out how many month's pay you're willing to risk in this way before you cut your losses. To my mind that should be a small number -- partly because it's your living and partly because the more they owe you the more you can fall into the "sunk cost" fallacy. There are plenty of people in the world for whom it is 0, and I don't think there's any shame in being one of them.
You should not threaten to leave until you're actually ready to go, because you shouldn't make an idle threat. Aside from being poor behavior, it damages your credibility for the future.
You should let your employer know (not aggressively) that the unreliability is a real problem for you, both financially and in terms of your confidence for the future of the business. You could also ask if they're willing to make good the losses you've suffered as a result of late payment (that is, any interest or other costs associated with your debts). This will make sure they see the late payment as a problem for you and for them, not just something they can do with no risk and no cost.
You don't have to threaten to look for other jobs, they'll surely figure out that if you're not happy and they're not paying you on time, there's a chance you'll find someone who will. You should look around enough to be sure of your options if you leave. And if you decide you want to go at a point where they're behind on pay then you probably don't have to work notice if you don't want to -- but you might never get the back pay if you don't!
I talked with the CEO, he said that as there are holidays in China so all the payments are delayed
There is indeed a holiday in China, but it has not been going on since November! Beware when people explain why they can't do what they're supposed to right now, but not why they didn't do it when they were supposed to. It's a sign that it's just an excuse, not the real reason. If you still haven't been paid next week then increase your estimate of your boss's dishonesty/unreliability and factor that into whether it's a good place to work.
Personally I would only take the offered 1/4 pay if it would make a practical difference. Find out what date they expect to pay you, compare it to the dates of your bills or planned expenses. And remember the date they say -- if you're not paid on that date then you can use it to remind them that they have a problem they need to solve. If they can't give you a date they expect to pay you, maybe take the money to be safe.
[*] Actually I tell a slight lie, there is. If your company is negotiating for investment or other money coming in then they may be unable to to tell you the details or in extreme cases even the existence of the negotiation. But in good conscience they must at least admit on the day that they aren't paying you and they don't have the money. Preferably before.
[**] This has happened to me. I wasn't in debt, so I knew for sure I could afford the risk. Since I don't know what your employment market is like, I can't tell whether you need to take this kind of risk in order to get on, or whether your employer is just exploiting you in a way that the next employer wouldn't.
