Sad news. It's worrying how little people know about the different types of stroke and how various people can be affected. My friend did research into couples coping after one partner has a stroke. She gave ordinary people a questionnaire as part of her research and was surprised at how little awareness there was. There really is a wide scale of outcomes and these can also depend on an individual's general health status. For example, my dad had a stroke which, in itself, was not a catastrophic one. However, his general health was already poor and this prevented his recovery. He died three years later and we found out that his stroke was called 'progressive' (in other words would lead to more deterioration rather than recovery). His other impairments contributed. The most important thing is to seek immediate treatment because, as others have said, it can be crucial in determining the level of recovery. An emergency doctor checked dad over and said he'd initially had a 'mini-stroke' and should rest but did not admit him to hospital and he had the bigger one a 24 hours later. Had he been admitted, this might have been prevented. The FAST campaign, horrible as it looked, was a good way of pushing this.
I hope Andrew Marr recovers well, even if things look bad at the moment.