Medium/Headscratchers

What is going on at the start of Season 4?
 * They have random people in the street asked about what happened at the end of the previous season . Why?

Joe's father is also sometimes confusing. He says in the episode "Burn, Baby Burn" (Season 4) that the deceased cannot see anything about those that they love, yet in previous seasons, he appears to Allison about advice about Joe's mother (the same person who he now knows nothing about). Whats the deal with that?
 * It's more that they can't se EVERYTHING about their loved ones.