When DHs parents passed away a few years ago he and his brother decided to go 50/50 on a holiday home near Nice. It's near a village, quiet, close enough to Nice for day trips. It has 6 bedrooms. So DH and I have one, his brother and his wife, then the 4 kids (our 2 and our two nephews). It's not fancy but we love it, a great use of his parents money as his mother was French and hated how disconnected her sons had become!
DD (24) makes more use than anyone else. She WFH Monday and Friday, likes to ski etc. So while in summer it's in almost constant use, DD uses it as a base to go skiing in the winter (flies out Thursday after work, works Friday, dinner out, skis Saturday, home Sunday or Monday). She's been with her boyfriend for almost a year and he's been going with her most of the winter. The deal we have is DH and his brother cover upkeep and bills but when you leave you have to book the cleaner (local) and pay for that, so it's clean for the next people. DD always does it.
Over the last couple of weeks we have all made our first trips of the year, DH and I will go 3 or 4 more times, his brother similar. The kids just go when they want. We do let friends use it but no one planned until a week in July. It's in perfect condition so no concerns. It's rural we keep a small car (DD uses it for skiing) and a scooter in the garage.
DDs boyfriend is due to sit an important exam for work in May, he has 3 weeks study leave, lives in a house share. DD has offered him her flat on the days she works from the office but it is in a busy part of London so not ideal. DD asked if we would let her boyfriend fly out and spend the 3 weeks there, she'd go out Thursday night - Sunday/Monday each week, but no one has any plans to go and even if they did there would be plenty of space. She thinks being somewhere isolated would be better for his studying. He has ADHD easily distracted etc.
DHs brother is fine with this, he said he may be out with his wife for a week of it but will be quiet and considerate etc.
DH however is unsure, he thinks it's a really bad idea. We'd need to get some things in order like insurance. But he knows the house well, knows the area better now and I'm keen to help.
DH thinks we don't know him well enough and what If he trashes it.
Frankly we don't his brothers friends but he doesn't object to them staying so it seems odd!
AIBU thinking we should let him go out and study, this may be the man DD marries and showing him some kindness may work in our favour!