Son newly diagnosed

My son (31) was admitted to hospital 3 weeks ago after optician found an issue. He had had “migraines” for 2 months numerous trips to gp ,out of hours & hospital all said migraines then optician sent him straight to a&e to be told brain tumour a week later we got the devastating news it was malignant & had spread to his spine he’s now getting op number 5 as his shunt constantly has problems & had a massive seizure today.  We have been told it’s a rare tumour & more testing needed done but still don’t know next steps regarding treatments   We also have been told it flagged up on a scan a few years ago but wasn’t followed up which is frustrating