Он, наверное, не сказал им об этом,

Он, наверное, не сказал им об этом, и они, возможно, не придут.

Results (English) 1:

He probably did not tell them about it and they may not come.

Results (English) 2:

He probably did not tell them about it and they could not come.

Results (English) 3:

He was, I think, is not said to them about this, and that they may not come.