Ed needs to stop and consider that WANTING to do something and being able to obtain that goal are not the same thing. The ONLY guarantee is that you get to make the attempt,and many,many people fail.
If he enlists in the Navy in order to attend BUDS training to become a SEAL and flunks out,he ends up having to serve years as a regular sailor. Mo betta to stay in the Marines and volunteer for Force Recon.