Squealer says that Boxer is going to be sent to the hospital and that Napoleon is sacrificing great amounts of money to ensure that Boxer gets the best care and medicines.
Boxer is actually sent to the knacker. The knacker is a horse slaughterer who will use Boxer's parts for glue. Thus we can believe that Napoleon was to make good money off of this.
Squealer professes that Boxer's last hours are spent saying that Napoleon is always right, and that we must keep working hard, and he whispered in Squealer's ear that Animal Farm must live on. It was very inspirational according to Squealer.
Squealer says that Boxer will be sent to a hospital for animals in a place called Willingdon. But what actually happens is that a van for a horse slaughtering company comes to get him. The idea is that he is being sold for money.
Squealer says that the van was not really from the slaughter house but was actually from the hospital. He says that Boxer spent his last hours in comfort, getting every possible sort of "attention" that a horse could get. Squealer says Boxer was only sad that he didn't live to see the windmill done. He says that Boxer's last words were praise for Napoleon.