Good nutrition is important as diet not only effects health but also mood, sleep and ability to learn.
Once you have identified patterns in preferred textures / colour you could experiment when offering fruit and vegetables e.g. fresh (soft), frozen (crunchy and cold), dried (crunchy and room temperature), smoothie (liquid), frozen into an ice- lolly (cold and a more consistent texture). You could also add food colouring to change to preferred colours.
Giving fortified alternatives of bread, milk, cereal, squash or juice can improve the nutrient content of the diet.
You may also be able to fortify the diet by adding ground nuts, nutritional yeast, blended vegetables into savoury sauces. You could boil pasta / rice in milk or milk alternatives.
A severely restricted diet has been linked to low levels of certain nutrients (vitamins B3, B6, C, calcium, iron and zinc).
It may be beneficial for your child to take a multivitamin and mineral supplement. These are available in liquid or chewy preparations. The liquid preparations can sometimes be added to accepted drinks. It might be useful to ensure the supplement contains iron.
Limiting foods which are high in fat or sugar to minimise risk of obesity or filling up on non-nutritious foods.