Tarzan Finds a Son! (1939) on Netflix

After an airplane crashes on the escarpment, a baby is found to be the only survivor. The child is rescued and is taken in by Jane and Tarzan. The jungle lord names him Boy and as the years go by, the child learns the way of the jungle and they all live a very happy life. Five years after the crash, a party from England arrive looking for the crash site and in the feint hope that there may have been survivors. Led by Sir Thomas Lancing, it seems that Boy has inherited a large fortune and wants to to take him back to England. Tarzan won't hear of it but Jane realizes that it may be in the child's best interest to return, even if it will break her heart. Her decision may end her relationship with her mate however.