It depends. If there are extenuating circumstances, he will have your back and give you the space to go off and be ill and recover, or to care for a dying parent or whatever it may be. He will work with you to make sure work is shared out to deputies or other teams, that sort of thing. That implies someone who usually performs well, but life has got in the way, and I think is different from someone who just isn’t so good.
When they're just crap, from what I've seen, he will try to focus on what they are good at, and if possible, make that their focus. He's also keen on training and we've had some pretty good courses over the years, and I think that can be helpful when someone is quite inexperienced and struggling with the demands of a new role which is a step up, be it prioritisation or dealing with different cultures or whatever else.
He is generally quite laissez faire, and will tell people what he wants to happen, but will then leave them to it - this is partly through necessity, because he has a massive global team, and travels a lot, so just can't be available at all times for people in Singapore and Canada and Colombia and Germany and so on all at once (we benefit from him being Europe-based.) However, if someone isn't doing so well, he will get more focussed on them, setting smaller goals rather than one overall one, with more deadlines.
What we have recently experienced is quite a major reorg - some of this was for entirely sensible reasons, with two departments covering similar roles, so it's made sense to merge them and split the teams differently to avoid duplication (and I can foresee some redundancies a bit further down the road.) As part of this, he took the opportunity to rejig the teams so that one manager has lost quite a substantial number of staff, almost half of what he had had, and while it can be justified for operational reasons, quite a lot of it has been to reduce the number of people reporting to an under-performing manager and reduce the scale of what he's expected to deal with. Things are still settling down, so it remains to be seen if this will do the job, but it's mostly looking positive so far. I think director felt limited - he did comment (with no names,) that it can be almost impossible to get rid of staff in Germany and the Netherlands, and I wonder if he feels this is an area where he hasn't achieved his own best results - but that is pure speculation. Getting rid has clearly been a consideration, though.