Can a PN router be used to access BT as a stop gap - if so how?

[#1]

I know this may sound odd but a friend of mine (sods law, lives 3 hours away) parents are with BT for their internet and are having router issues.  BT keep promising to send a new router but dont so their daughter who is a loyal PN customer and has a spare Thomson 585v8 router was wondering if they can use that to get them onto the internet until a new router turns up from BT.
This saga of a new router coming has now been going on for over 2 weeks and her elderly parents love the internet (well who doesnt) so it would be nice to try and help get them set up.  Do any of you technically savy folks know how to do this and if so could you explain it in simple terms so that their daughter could set it up for them.  I can direct her to this forum.  I think it would be the final thing that would pry the old folks away and persuade them that PN are the future and that BT support staff are not as good as those the PN have in Sheffield nor do they have a forum like this with helful customers.
So folks, can you help, if not dont worry, I know its a long shot 

[#2]

Yes you can - just put the BT login etc in manually

[#3]

I think BT don't use passwords - they authenticate via the phone line number
So you can put literally anything in the router setup password field - best to use something rather than nothing.

[#4]

http://btybb.custhelp.com/app/answers/detail/a_id/7447/~/how-do-i-set-up-my-non-bt-router%3F
This explains