Glioblastoma GBM4

HI

My son who has N/F had been complaining of headaches back in Dec 2018.Had a MRI scan done in early 2019 which showed a tumour in the cerebellum..This was diiagnosed as an Astrocytoma he had surgery but unfortunately only over 20% could be removed as it was so close to the brain stem.He then had a course of radiation followed by chemo.Throughout this he was having 3 monthly scans which showed no great change in the tumour..In Feb 2021 his scan showed a slight increase in size so a Perfusion MRI scan was done.Following that scan his tumour has been classed as a Glioblastoma GBM4 which was devastating . They have now started him on Avastin chemo and plan to add Lomustine chemo tablet depending how he reacts to the first one.We feel so helpless and lost from been told not to worry its a low grade tumour to now a terminal one.. Is there anything we can do cancer trials other treatments. My son is only in his early 40s with a very young family. Any advice or help would be very much appreciated.

Thanks for taking the time to read my story

Update

Hi

After 2 sessions of Avastin my son developed an infection and had to stop all treatment. He is now 5 weeks off with this abcess which is slowly healing. His breathing is deteriorating and has to use wheelchair when out of the house. Things are just going from bad to worse we just need him to get back on treatment. Scan done this week showed no significant change in size of tumour since last March which we thought was good news.But pallative care nurse really rocked us today when she started talking about Cerebral Breathing, Seizures and DNR. She has prescribed Kepra and Bucon for him and arranging for hospital bed for his house. Has anyone got any information on Cerebral Breathing or any experience with these 2 drugs. Any information or helpful tips with dealing with his breathlessness would be greatly appreciated 

Thanks

Joe