The camera does a very good job on face pictures in Auto mode. There are almost an infinite amount of settings you can adjust when not in Auto but I would suggest not going there until you are more familiar with your camera. However the great thing about digital cameras is you see the instant results and no waste of film ! So if your grandchild will tolerate you taking multitudes of pictures don't be afraid of trying different settings if you want.
On close up pictures you want to be careful with the lighting and the use of the built in flash. I use an external flash with a light diffuser and I bounce the flash off the ceiling. I'm assuming you will be indoors, if your outside just using Auto will get you excellent pictures.
Try using it without the built in flash, use room lighting add some if you need to.
Or use the flash and the flash compensation settings to tone down the power of the flash. You can lower it to a minus 2 setting. It's on page 144 of the user manual.
Don't get overwhelmed like I said it takes beautiful pictures with no or very little input from us the user !
Im going to include a link from a professional photograper M West on you tube who does a whole series on digital photograpy. He speaks in simple terms, with great examples. And what is really awesome is he uses the SX50HS for all his lessons! I watched and still watch them to learn. I think you will learn a lot from them and he breaks them down into different topics and areas of photograpy. I think there may be one on faces or portraits as well as flash photograpy.
https://www.youtube.com/user/MWESTPhotography
Congradulations on the grandchild !!
