As a graduate of l'Ecole du Genie et de l'Artillerie in Metz he would automatically receive low-grade officer rank. However, the enlistment document, based on the general call-up decree of 20 January 1813 for the class of 1814 shows that he reached, or entered in, the rank of ''corporel".in the 24th light infantry regiment but was demoted six weeks later. He was recruited in the Sarre Department.
The enlistment document is located in the Service Historique de la Defense at Vincennes and the file no. is in my possession. He arrived at his military division on 5 April 1813. I repeat: there is no entry under the "former service" column of any earlier campaign. The column only states that he was hospitalized on 29 January 1814 [surely at the brief Battle of Brienne] and de-mobilised from his regiment on 11 August 1814.
The accounts in 2 obituaries of 1884 do not conform to the enlistment document. Enlisting in April 1813 (document) would, however, allow for his safe retreat from Moscow and re-enlistment. Except this is not a re-enlistment as I understand it. His name was on a call-up list.
One solution is that the regiment he joined did fight in the Russian campaign (Borodino) and that this turned into a family legend that he fought in this campaign. Thus the line between fact and fiction is blurred by accretions over the years. The difficulty is that this soldier lived for many years with his son until his death in 1884 and it is almost certain that this son wrote one of the obituaries. The obituary does not magnify any military exploits.