Selling the house is a red herring, too. Sy you get an offer, in my bitter experience it takes 3 months to actually move - especially as you would need to buy simultaneously. You just cAN'T have him in the house through the summer hols - his behaviour last summer hols, arund the boys playing, is EXACTLY why you are laving him!
And, as Tribpot says, any decision about price is not his and his alone.
House sales have apparantly been in abeyance because peopel have been watching the football - maybe there will be a surge, now.
He has to rent somewhere. Why can't he get on wth that? Was he going to stay with the freind for months and months while the house sold?
I am sure you can get him turfed out - your HV will surely write a statement about the stress of last summer - and that business of the senco saying ds1 had to do messy play and H wouldn't let him even get one bit of gravel from the frive on the patio. Grrrrr. He has to be MADE to go if he won't do it under his own steam.
You don't deserve this hassle, lw, it isn't fair.