I have found this on the RN Website
Q. Are there age limits for recruits?The age limits for each branch are quoted on the relevant job page. Rating/ Other Rank recruits must be within this age limit on the day of entry to HMS Raleigh/ CTC RM Lympstone, including the following birthday. For example, recruits can join most branches between the ages of 16 and 36, including the 37th birthday. Officer entrants must be within the quoted age limit on the first day of the month of entry to Britannia Royal Naval College/ CTC RM Lympstone. The latest entry for the RNR is generally before your 40th birthday although ex-RN applications will be considered up to the age of 45.
n.b. The Armed Forces (with the exception of the Royal Fleet Auxiliary) have a complete exemption, in terms of maintaining operational (combat) effectiveness, from the provisions of the Employment Equality (Age) Regulations 2006.
If the crunch comes, he could always join the Danish Hjemmevaern (Home Guard). They have a Unit where there is no upper age limit! You need to have been resident in Denmark for a year and speak Danish, that all......
I'm sure Britain will follow suit, once the Equality Bill goes through.... :twisted:
The age limit for him joining could be slightly different. The basic rule is that his accumulated time (Army and RN) will need to total 18 years service by his 55 birthday. So basically it will depend on how much Army service he did. The best thing for him is to pop into his nearest AFCO with all his discharge paperwork and they can then send off to see if he could be processed for joining.