Awareness of the effects of gravity allows them to hold an object that is placed in their hand or rolled to their hand. They will also notice when it falls out of their hand, but may not be able to tighten their grip to prevent the fall. Precautions about size, cleanliness, etc., need to be taken because anything that goes into their hand may also go into their mouth.
Hand-over-hand assistance with a bean bag and a metronome is the beginning of activities that need to be created for these people. We need more.