Does Holden have any guilt feelings about Allie, and do you feel this is normal?

Holden feels anger, self-denial, and yes, guilt, over Allie's death. He loved Allie and blames himself for his brother's death, as people generally do. That's why he punched out all the windows in the garage. That's why he slipped into such a heavy depression with mental anxiety. Is this abnormal? Hard to say. We have to keep in mind that JD Salinger is a WWII veteran who most likely had PTSD. That same mental anxiety and depression he had, he also wrote in for Holden (whether intentional or not). Holden's reaction to Allie's death is very plausible and therefore perhaps even normal.