Hi

Advanced Merchant's point should be carefully considered. Business and personal principles aren't always the best companions, if you can find a way to get the site back up and manage a move over time, then do so.

The outcome of sustained downtime really is site dependent but a site we became involved with recently is in a similar position. This was down for about 9 days, until the end of June, then back up
1st July. If there has been a surprise, that was how dramatically their SERPs have suffered, so make sure your owners are aware of the cost their principles may have. Very much in line with the case you outline, the site I mentioned is by no means a large or important website but did have a few very useful and consistent page 1 slots. With the inevitable delayed action, they have seriously dived.

Everything possible has been done, solid hosting and a few fresh draws for bots but the first real sign of retrieving the position only came late last night, with the site limping onto the bottom of page 1 for their least competitive term (they were at the top). As said before, there is no set rule but from other cases that have been reported, this period of weeks, rather than months does seem typical. The upside is, others in the same position have stated that when recovery does start, this tends to accelerate by itself.

Again, avoid the situation if you can but good luck either way.