I have 3 wooden look carved different height candle holders I would li

white wash them

Chalk paint them all off white and use a little silver accent paint and seal with clear wax or pick three colors and use a dark wax. Look at Annie Sloan videos on YouTube or look on Pinterest under Candle holder ideas.

If they are plastic, use a spray paint for plastic, if they are metal, Rustoleum, if they are wood or plaster, you should be able to paint with whatever you want. Check out different colors to see what you think will go with her décor. You may want to go shiny or you could go matte, whatever will help get color into her all gray living room. Perhaps she could get some pillows or something in the same colors you use in the candle holders and the candles you put with them. I would say most colors will go well with the gray she has now.

For an all gray living room, painting them white, then going over them with a little touch of gray in the creases, not a lot. I think that would look great!

Spray white & touch up with Rub N Buff. It comes in lots of colors