Is there any way to stream video from camera when the phone is locked?

Question

I'm using video call on an android phone in order to keep an eye on my grandmother 24/7. The thing is that the light from the screen is troubling her to sleep, but when she locks the phone, the camera turns off. Is there anything I could do? Until recently, you could use discord with locked screen and the camera was working perfectly, but that changed last week, and now even video call on discord turns off when the screen is locked. Thanks!