I'm so sorry to hear about your mother being sectioned. I can really understand how scared and worried you must be feeling, as exactly the same thing happened to my own Mum two years ago - strangely enough, it was on 1 Dec 2012, so it all tends to come back into my mind at this time of year. In my Mum's case, she was sectioned in the middle of the night via the ambulance service (I lived 250 miles away and had called out NHS 24 to check on her, as I had sensed something was very wrong during my usual late-night call to her). My Mum was 89 at the time and was clearly having major difficulties (did not know day/night, could not longer cook or use household appliances, no longer washed or changed her clothes, would not let anyone in her house and was very suspicious of all of her neighbours, the GP etc). I had been her long-distance carer for 6 years, also visiting as often as I could, but as she totally refused all help from anyone other than me, she had no formal diagnosis.
Being sectioned was, in my Mum's case, the first step in getting proper medical help for her, and because she was actually in a mental health assessment unit in a large hospital, she had immediate access to expert care in all areas. When I visited her the day after she was admitted, she was scared and upset (particularly as some of the other patients were very noisy and were much more obviously disturbed than her). After a few days, however, she really began to improve - physically because she was eating properly and had begun to accept help with washing, but also mentally (for the first time she admitted in a session with her consultant psychiatrist that she did have difficulties, both with her memory and with managing on her own at home). Once my Mum started to accept care, the section was lifted and she became a voluntary patient. After a month of assessment, she was diagnosed with moderate AD and started on donepezil and zopliclone. For the first time in years she started to have a normal day/night routine, and to become much more content. She was in the assessment unit for ten weeks, and then was moved to a community hospital for another two months while a social services assessment was done to see if she could return home with a care package, or if she needed to go into a care home. It was decided that she did need 24-hour care, and arrangements were then made for her to move to a care home. She wanted to be near me, which meant a move from Scotland to England (hence the need to involve Social Services although she was self-funding, as the Scottish LA agreed to pay the personal care element normally only available in Scotland). She moved to the care home four months after being sectioned, without ever going back to her house (which by then she had forgotten, although she could still recognise it in photos). In the care home, she was well looked after, happy and I was able to see her every day - her quality of life was vastly improved in comparison to before her time in the mental health assessment unit. Sadly she caught norovirus, then a severe UTI in June 2014 and died in hospital, but before that she had over a year when she enjoyed many aspects of life again.
I still miss my little Mum dreadfully, and over the past few years have had many times when I have felt full of despair and guilt - but mostly these times were before she was sectioned, because then it was so difficult to get support for her and I felt I was struggling on my own. After she was sectioned, the paths/options for Mum became clearer and I did finally have access to a lot of expert help. I really hope that it will be the same for you, and that although things are really difficult at the moment, your mother will get the appropriate treatment/medication and that her quality of life will improve. Two years ago at the start of December I felt truly at rock bottom, but the sectioning was a turning point and things honestly did get better quite quickly - by January Mum's medication was working and she had become much calmer and more accepting of help. By May when she moved to the care home, she had recovered quite a bit of her old personality again, and enjoyed doing many activities (singing, crafts, growing plants). So I would say that although the sectioning process is truly awful, you are at least past the first stage of it and your mother is now in the system and will hopefully be getting the assessment/medication she needs. I wish you and your mother the very best.