Sorry to read of your loss, it must be devastating for you! Things that may help your mum:- the right medication (eg, in my case, rasagiline/Azilect), a local PD support group, regular exercise, daily organic raw virgin coconut oil, avocado, cinnamon, turmeric, omega-3 and (as I hope to discover soon) low-dose naltrexone (LDN).
Some time ago I was diagnosed with COPD, although I had never smoked, but later the doctors changed their minds and now I don't even have any asthma symptoms - all very mysterious!
So don't - whatever you do - give up or lose your sense of humour. As a Christian most of my adult life, I was amused by a funny thought that came to me last night - that people with Parkinson's 'work out (in the sense of complete/see through to the finish) their salvation with fear and trembling'... would you believe a reference to my tremor in the Bible, Paul's letter to the Philippians ch2,v12? Well, I thought it was funny, anyway!
All the very best to you and your mum.