It is unclear from your description how old you son is and whether there were any other associated symptoms noted upon birth, or whether the sole finding was the loss of both big toes. Assuming that there are no other associated finding,s for the most part, it is unlikely that this should affect his ability to walk or carry about normal day to day activities, and it is also unlikely that this should affect his development as his body will learn to compensate for the fact that he does not have his big toes. Because being born without both big toes may be due to some underlying genetic condition, it is very important that you have your child and your family evaluated by a geneticist
or start with your primary care doctor
because there may be some underlying genetic condition that one or both of the parents may be harboring and that he may share. They would also be able to run further tests and give you more information on what could be the underlying cause for this and what other issues you may have to look out for in the future.