First, I am so sorry to read about your Mum's decline in health. I lost my Mum to lung cancer a few weeks ago and even as a palliative nurse I found it tough to watch her go through it. She had mets to the brain. In the last 2-3 weeks of her life Mum started to lose her ability to swallow and is usually an indication of what is termed pre-active dying. Everyone's road to death is unique and no one can ever say how long a patient has, however there are indicators we go by. The swallowing is because the message to swallow starts to be lost. Appetite goes as the body simply does not require the food anymore, it is going through a natural process in preparation for death. The body does not need food for energy. In some cases it can be detrimental in the dying process. Your Mum will probably start to drink less, again all typical. Moisten her lips and her nurses should be able to show you how and guide you on what to use. Just like the body prepares us for birth. The oppposite is true when we are dying. Your Mum will start to sleep a lot more and in deeper sleep. She will start to withdraw from conversation and may even wish to be left alone. All so natural. There may be some agitation and/or anxiety, Mum might speak to people that she can see but you can't. Toxins will build in her system which can cause the agitation. Do not be frightened by it, reassure your Mum and speak to her, she will be able to hear you. I softly massaged my Mum's feet, legs and stroked her head gently to help keep her calm. I spoke to her gently and knew when she just didn't want any conversation, just quiet. Mum had the syringe driver fitted 2 weeks before she passed and also had the butterfly fitted for breakthrough unettledness or discomfort. 
Take this precious time to say the things you need to and tell her you love her and thank her for all of the great things she did for and gave you, her advice, support, everything you can think of. It is your chance to do it before she loses consciousness and slips away. It is hard and overwhelming embrace rather than fear the end of her life. It is how she taught you. My love and care are with you and your family. Smile and look for your sunrise, your Mum will always be with you.

Wow thank you for reply   and exactly  what I needed to hear thank you and sorry to hear about your mum .