It's wonderful that something she loves to do sort of fell into her lap like that.

If she needs her colors to be bright, she needs to apply a coat of white in the areas she's going to paint first. If the wood is very slick, she might need to rough it up just a little with sand paper (just like you would do with furniture prior to applying paint) so the white layer or sealer will adhere. If she uses a sealer, it will need to be white. Another possibility would be gesso. I would ask an art supply store or similar business if gesso would be the best thing to use. Gesso is what artists put on canvas prior to painting.

Wish her luck for me, ok?