Truly appalling and nonsensical.
Surely anyone in the Army is on the MoD payroll hence are acting under the order of the Government. So if the Government sends him abroad, what right have the Government to use this as a reason for a citizenship.
And if someone fulfills the requirements for Indefinte Leave to Remain, why not for a passport.
It's a sad fact that many people who apply for citizenship need to mploy the services of a solicitor; I hope this chap can get good advice next time.
Cheers
Whirls