Dear Conny,
First of all welcome to our site and our wonderful community. May you find much comfort and reassurance here.
I was diagnosed at the age of 22 years old back in may 2017 and I am now 23. I had to pause my studies and move back home with my parents. I have to say the support of my parents was what got me through the darkest of days and I will be forever grateful for their unconditional love. I wasn’t always easy, but they loved me so very much and knowing that I just couldn’t give up and I knew I had to keep fighting. And now I am finally in a happy place in my life after such a long time. You may have your ups and downs but this journey does bring you so much closer even if you originally thought you were super close. The love you have for eachother through the most challenging time in your sons life will really shine through and it will mean the absolute world to him. You don’t have to be perfect, take it from me, my parents had their fair share of times when their strong masks cracked. You are only human. You might not be able to remove your sons AVM but your love and support is a bigger deal than you could ever realise. Because of my parents I have faught through this and continue to fight and I am a better version of me.
Here is my latest post, I hope it doesn’t scare you and instead shows you despite being young we can overcome alot and get out the other side. This experience also builds our charictor and makes us better people and because we are young I believe it benefits us with helpful adaptability: My left occipital embolisation story
If you like I could send you me and my mothers mobile numbers and we could call via whatsapp so its free. I am sure my mum would love to talk to a fellow mum too 
PM me if interested but no pressure at all, always here for you on this site regardless.
Best of wishes for you and your son,
Corrine