Hiya Richierich
I take it the lady had a general anaesthetic? This can have pretty profound effects on someone with dementia and takes longer than normal to leave their system. The dementia can appear as though there has been a big deterioration but over time some capacity can be regained, if not all. Apart from the effect of the anaesthetic, you also have to contend with the increased confusion of being in hospital surrounded by strangers.
Your friend can help by spending as much time at the hospital as possible. Not all staff will remember about the dementia and even if they do they don't always have the time to give the person the level of attention that they need. Being there also stops other accidents happening such as them forgetting to ask for help in walking etc. even after major surgery you will be amazed at how quickly they can forget what is happening. Another benefit of being at the hospital as much as you can be is that you can be around when the likes of the physiotherapists are around because the dementia person,might have problems following instructions, the physiotherapists don't have the time to give the extra help and very often the physiotherapy is stopped because they say the person is unable to cooperate.
I hope your friend has plenty of leave left! LOL
Fiona
