Reduce access to certain foods. Substitute similar foods that are healthy. Use sturdy plastic dishes and cups for minimum breakage. The tablecloth and dishes should be of contrasting colors to make dishes easy to distiguish from their background. Use plastic smocks or aprons.
Eating utensils with built-up handles are easier to manipulate.
These are available in medical supply stores and catalogs. Tape can also be wrapped around utensil handles to build them up. Plates with suction cups will prevent sliding. Also, plates with guards or dividers help prevent food from slipping off plate. Other aides include controlled flow drinking cups and clip-on straw holders which are available at medical supply stores or catalogues.