oesophagus cancer - constant saliva

After my Mum was diagnosed with cancer during COVID and following chemo and radiotherapy she was told that an operation wasn't possible. She was fairly quickly fitted with a feeding tube in down her throat and after many months finally fitted with a tube directly feeding through her stomach, which was loads better with regards to both time and ease of moving around.  Unfortunately this "freedom"  proved to be short-lived as time has passed she is increasingly finding the constant saliva and more recently the incessant build up of mucus causing need to cough to clear, absolutely exhausting. I'm hoping to find someone who may be in a similar position or hopefully someone who has been in a similar position but found something that has helped.  She has accepted that she is never going to be able to eat/drink/swallow again but I really would like her to have some quality of life.  I am acting as her voice as she a) finds it upsetting and b) my parents live abroad - I'm trying to filter any negative responses/posts  but being so far away and so helpless I just want to help in any way I can