Sorry to hear that. Keep him happy and spend a lot of time with him. Sucks that he’s so young. My pup is also sick but she’s almost 15yrs old so that makes it more tolerable- we’ve been battling various issues for several years now -Cushings, ruptured spinal disc (now repaired) and congestive heart failure- she sleeps most of the time now. It’s going to be tough for you but time heals all wounds.
Happier days