Yes, you can use assistive touch in the general settings, and the person saying you'll need to repair the phone, that is a must. But to bypass the silent switch, you can use assistive touch until you get your phone serviced. Go to Settings > General > Accessibility > AssistiveTouch > toggle on > and tap the little white ball at on the screen (it will appear on left top as default) you can move the ball if you want.
Tap the ball, tap on device, tap on mute/unmute. You are set to bypass the silent switch now.
I hope this can help you.