Wait and see is probably the best bet. The recent decline just started, after all, trying to take a position quickly may make you get some unnecessary losses when you could've planned it out much better. Definitely not the time to enter and expect Bitcoin going up, but if they really want to, they can try spreading out their investment times to different periods, just so that you won't lose everything by entering now or entering later. Profit is smaller, but hey, that's the price for it.
Wait and see is a line for those who arent really sure about their capacities and capabilities towards trading or investment where you do wait when the market would have risen up already?
When it comes to times like these then you would need to make some action but there are instances on where patience would be tested out.
Honestly this is the best time on buying coins while its still on sale but of course purchase with your own risk.