
Within days. Primarily an access and egress problem rather than a structural one. The tree has already done the thing you were afraid of. The hazard that remains is stored energy in the wood — trunk sections under bind, and spring poles among the bent saplings underneath — which is a cutting hazard, not a falling one.
Days is reasonable, with two exceptions that make it immediate: if it blocks the only route out for someone with a medical need, or if it obstructs a fire lane or emergency access. Otherwise the risk does not grow while it sits. What does change is the wood — the trunk dries, settles and shifts its bind points over a week or two, so cuts that would have been predictable on day one can pinch a bar and move unexpectedly later.