Im not sure if it would work.It may be too brittle.The extreme outer hoof wall is the only part that i would think would be hard enough and it is pretty thin.When i have examined hoof trimmings,after the trim and after is has dried,it tends to get pretty brittle .I dont know if i would trust it,for a tip overlay.
Chances are,based on your description,the horse experienced a case of laminitis or even full blown founder and in that case,the hoof walls integrity was compromised as well.