Chuck can bring Katey certain items as gifts for prestige points. There are a total of 11 gifts that Chuck can give to Katey. The first gift will merit the "Father of the Month" achievement and giving all 11 will merit the "Father of the year" achievement. The gifts (and images of a location for them) are listed below in no particular order.
Prestige Points are rewarded to chuck for giving Katey gifts. The only exception to this is Snowflake, who will reward you 5,000 PP for "giving" her to Katie (along with a special message), but also gives you "rescue" PP for just bringing Snowflake to the safe house.
It is possible to go from level 1 to level 6 JUST from gifting items to Katey (no Zombie killing required)[11].
In Case Zero if Katey is not given Zombrex there is a cutscene and the game is over. In Dead Rising 2 there is also a cutscene but the game will continue. When Chuck returns to the security room in the Safe House there is a second cutscene similar to Case Zero's cutscene if Chuck is outside the Brockett Gas Station when she turned. Chuck drops to his knees, pounding his fist on the ground in both scenes.