What's the Name of That Book??? discussion

read around 2008, book felt relatively old at the time.
Boy lives in a rural/suburban area with his relatively poor family, his mom is the primary positive parent. Bullied at school, he has an imaginary friend (they look identical) that only he can see (maybe a friend could??) which exacerbates the bullying. His best friend may have said he believes in the imaginary friend only to take it back later. Main character has an old man as a positive mentor/role-model who totally believes in his imaginary friend (may have one himself). The community has a conflict about the construction/demolition of a local dam.
Spoiler:






Old man teaches boy how to make his imaginary friend visible (maybe via demonstration?). Boy then uses this to confound dam workers. Book ends with people thinking it was actually the boy, but he has an alibi, as he was with people (mom?) the whole time.

Do you remember the cover?
Part of a series?
Do you remember the time period the story takes place?

I'm pretty sure this was a single book, not part of a series, grey-green cover, takes place before cell-phones are a thing, but in modern times (cars, excavators, electricity are all taken for granted.

Belly Flop?

Note: Aahnix (OP) was last active on the site January 2020.

The Bodach=The Walking Stones, by Mollie Hunter?

"Young Donald Campbell is excited when he learns that a hydroelectric dam will be built in his glen. The dam was foreseen by the Bodach, an old man who lives nearby. But even as Donald and the whole town become excited by the idea of the dam the Bodach declares that the glen will not be flooded until he gives his leave. Over many seasons the dam is constructed but the Bodach refuses to move to his new home. Instead, he stays in the glen. When Royalty shows up to start the dam working, the workers shut it back down shortly after for they will not be party to the drowning of an old man. The crew then set out in pursuit of the old man, but they can never catch him. Just when they think they are close, he is suddenly on the other side of the glen.
As Donald tries to understand the Bodach's reasons, he learns of the legends surrounding the stone circle that occupies a part of the glen. The stones are said to walk to the river once every hundred years and the time is fast approaching. But then Donald learns something even more astounding, the Bodach has been training him to be his successor and will be given the second sight in a strange ritual."

No response, moving to Abandoned folder.

Aahnix (OP) was last active on the site in January 2020.