This is a very good question, and my hat is off to you for taking your time to help this child with a cleft. I wish that I could get a little more information from you to be able to answer your questions more completely, but due to the nature of this forum I am not able to...the short answer is "yes" I would recommend having this child referred to see a specialist. If they are in the United States, there are many different "Cleft Clinics" that involve multi-specialty physicians that all approach the different problems that cleft patients have in a holistic manner (meaning complete care).
As you well know "clefts" occur when there is a disruption in embryological development. Normally the embryonic structures that end up being the palate and lip migrate and fuse in the midline, and when this process stops before it is complete, they are left with a "cleft". Clefts can be of the lip, hard palate, or soft palate (you mentioned both lip and palate), can be unilateral or bilateral, and can be partial or complete. You can imagine that the worse the cleft (bilateral complete for example), the worse feeding/speech problems the child has, and the harder the defect is to correct surgically. All the more reason to get the child into a center that does a lot of cleft work, and can evaluate them fully. But to answer your question, a prosthodontic evaluation should be part of this process. I hope this is helpful.