AIBU to tell my husband not to be a best man

[howfartospar]

My DH worked for a company about 10 years ago.
He got pally with one of the people in his team as they had a lot of similar interests.
Then this other chap joined their department, who'd just left the paratroopers.
He apparently was very aggressive in work, was often rude to my DH and wasn't "his cup of tea."
However, the 3 of them did used to socialise on an infrequent basis.
This guy is getting married shortly and my DH was shocked to be asked to be best man. He figured this guy, doesn't actually have close friends, is struggling to adapt to civvy street and is reluctantly going ahead as best man.DH has organised a weekend in Newcastle for a stag, and now it turns out lots of squaddie types are going.
I've said that he can turn down this offer of being best man as he owes this guy no loyalty (particularly after being so rude to him on occasions)
AIBU or should my DH just do this their special day?

The bit that is missing from your story is, does your DH want to be this bloke's best man? If he wants to, he should just get on with it and not clutch his pearls at all the dreadful rough squaddies that will turn up (rolling my eyes so hard here i can see my own brain). If he doesn't want to, he should contact his mate and say he doesn't want to do it any more.

Very odd that he knows a bunch of people from the military well enough to ask to a stag but not better than you DH to be best man?
Ultimately its down to your DH to make his own choice, you don't really get a vote here.

I'm confused by why you think its your place to tell him what to do?

Either he wants to do it or he doesn't. He's a grown man and can make his own mind up!

To update, he doesn't really want to do it but will go ahead rather than have an awkward conversation.
DH us quite passive, this guy is the opposite and assuming his military pals may be similar. (No disrespect intended)
As this has gone on my DH has invested time and money into the stag do and wedding, and it doesn't "feel right"( his own words)
I'm suggesting he doesn't have to go through with it but I suspect he will not to cause offence.

Exactly. It's up to him and nothing to do with you.

I agree that it's odd that this man has lots of military friends coming to the stag weekend, but isn't close enough to the group, to ask one to be his best man!!! If he was in the military with them, then I'd say he probably knows them better than your husband! To be honest your husband has two choices - he goes along to the stag weekend and wedding or he tells this man, he can no longer be best man or go to the stag weekend. There isn't any other choice.

'Squaddie types'. Gosh.