On Fri, 09 Jan 2015 19:39:06 -0500, micky
wrote:

(All the other houses drain the sump and the downspout underground
(after first going above ground) to the gutter. My house drains the
sump underground to the side of the stream bed. But his house isn't
close to either of these things. Well, it's close to the steam bed in
the back, but the sump pump is in the front)

So, then he should run some 1.5" PVC across the basement ceiling from
the front to the back of the house, and exit thru the back wall, then
put a pipe on the lawn and run it to the stream. (of course it has to
slope downhill or it will freeze). That would be fairly easy and cheap
to do.

Of course from reading this thread, it appears he wont do anything.
Then again, it's his property and not your concern. If he screws up his
house, that's his business, not yours. You can suggest things, but you
cant MAKE him do anything. If there is ice building up in YOUR yard,
then you might contact the local building inspectors.

Since you mentioned a stream next to the house, there is a good chance
that stream has underground channels or a spring, and it may be under
his basement.