What is the background of why your (former) friend decided to bring the trailer there? Maybe if you understand the motive it would help you and us know how to react..
Was it his responsibility to remove the trailer from its original place by a certain deadline? And because he couldn't meet the deadline he needed to scramble and place it somewhere (anywhere) to meet the deadline? Did he intend to notify you that he was parking it there temporarily and just couldn't get ahold of you prior to the truck making the delivery?
Was it a practical joke?
Was it an awkward attempt at 'getting you back' for something trivial that inconvenienced him in the past?
Did you say (half heartedly) at some point in casual conversation that if anyone needed a place to go with something that you have plenty of room 'out back' and then he took you up on it?
What did he intend for you to do with it, scrap it?
You don't have to give all the details, but it is strange enough to have someone dump anything on your property without telling you... much less a huge mobile home and all the logistics of getting it hauled and positioned on your property and then left there.
What is it worth in its current condition? Or for scrap value? If you ask to be reimbursed for damages and that is more than the scrap value of the mobile home your friend may just say fine, keep it and then you would be hard pressed to use the actual item for collateral with out an expensive small claims court case.
