Worried about GD's Diet

I hope I'm in the right section, this is my first post! I'm really worried about the foods my son & DIL feed my year old GD. Although DIL does not work, lunch is a baby jar, some baby crispy things, and a baby yoghurt, sometimes a banana. Tea is always bread & butter, cheese spread and more crispy things or baby cake. GD isn't allowed to try feeding herself (could be difficult with the jar stuff) and is constantly having her face & hands wiped during the meal. Even banana is fed to her with a spoon. I worry at the lack of variety in her food and the lack of nutrients from fresh fruit and vegetables. GD seems to get a lot of colds recently, I wonder if it's the diet, but daren't approach it in a direct way. Subtle hints and suggestions haven't worked.