It's time to get the pills for Larry. Start by talking with Doug, who is standing on the left, next to the wooden exit door. Select the "Let's have a look around" option. You will both get outside and see what is going on in the street. When you exit you can talk with Doug about his past (if you choose "How'd you end up here?", Doug will ask you another question). If you want to go back to the pharmacy, select "Go back inside.", or look to the right and use the door to enter the Pharmacy.
However, do not go back inside. Instead, take a look around the area from right to left. Look at the Boarded-Up Windows, a Lock on the gate, a Hardware Store and TV Store. That's everything, now it's time to act. First, use the photo of Lee's family on the Trapped Walker to make sure that he has the keys (it will turn out that the trapped zombie is actually Lee's brother).
Then, try to use the remote control you found earlier on the TV Store. You won't manage to turn any of the TVs on, however, Doug will use your idea and re-program the remote control. He will turn the TVs on, unfortunately, the noise they make is muffled by the windowpanes.
Use the axe on the Lock to break it, open the Gate Latch and then take a Brick lying right in front of the gate latch and throw it through the windowpane of the TV Store. It has worked - all the zombies are watching TV now. Take a look at the trapped zombie one more time - you'll be able to run up to him now - choose the "run" icon (Lee's Brother).
After a short conversation with your brother you will have to hit him with the axe five times, and then search his body. In this way you will find the pharmacy keys. Watch the cutscene. When it's finished you'll find yourself in the pharmacy office.
Use the keys to open the Door to Pharmacy and then just go inside. After a while, you'll hear an extremely loud alarm, which will complicate the situation very much...