I would share as much as you want with him. He may or maynot want more information. You may not want to share. You can share information, stories, fun times, healing times, etc.
I would say the healthiest way to share is to stay present and have him be a source of fun and encouragement and joy and LOVE.
Being there for him would be a great thing as you are able.
In any sense, you are not obligated to share.
There are some books for both you and him - of course he would read the sections on family, partners, friends: Victims No Longer by Mike Lew, Abused Boys by Mic Hunter or Ghost in the Bedroom.
He can also sign up here for there is a section for families and friends on here.
I may take sometime to feel loved again. For me I had to learn to love as I dealt with the memories of the abuse.
Keep coming back,
Live to your fullest potential
Never make someone a priority if your only an option