external speaker and front facing camera problem

Hello, my uncle has given me his iphone 5 and it seems to have a few problems. First is that when i call someone and put it on speaker, they cannot hear me while i can hear them, however this is not the issue when the phone is not on speaker. When it is not on speaker, the other party can hear me well. when i play music or make a video, the speaker works well. Another problem is that there is a problem with the front facing camera. When it is from the rear camera, i can see clearly and all works well like it should, however once i change the camera to front facing, the app either just freezes (showing nothing except a pause of the shutter opening animation), or pinkish lines come up. Please let me know what i can do or which part of the phone i have to replace to fix these issues, thank you.