Friend dilemma...

[user1483390742]

I used to have a best friend from the ages of 20- 35ish- worked together, kids around same time, hols together etc. She moved abroad 10 years ago and we lost touch..fair enough, life is busy.
She has got in touch with me again on FB and is coming home for a while. She wants to come and stay with her DH and 2 teenage DDs for 2 nights/3 days. My 2 teenage sons do not want them staying- they do not remember them.They say they will feel awkward with 2 teenage girls they don't know, sleeping in one of their bedrooms (the boys would have to bunk in together), and wandering around our house.
I get what they are saying completely. I don't even know if my friend and i have anything in common anymore! She can't afford to stay in a hotel/ b&b.
What shall i do?!

Why are they planning to come here if they can't afford anywhere to stay?

Just say no. You will regret it once they arrive. As you say you don't really have anything in common any more and it will make your own DC feel uncomfortable.
Whether she can afford anything else is not your problem. Why would they book flights/travel without having anywhere to stay? They assumed you would do it. They'll have to ask someone else or postpone their trip.
No is a complete sentence.

Sorry-they are coming home to her parents who live 200 miles from me. She wants to catch up!

Offer to head up there for a weekend by yourself?

Tried that- she thought it would be nice to get out from under her parents feet for a few days! No amount of hinting seems to be working!

Stop hinting.

"We don't have the space in our house to put you all up. Let's have lunch instead".

Something like that.