A coach can absolutely be the blame for an individual players play and stat lines.
It's his job to design the plays, and to see what is and isn't working for the players. It's his job to motivate players and get them out of slumps. If someone gives a puck away over and over, it needs to be corrected somehow.
If a line is playing great, yes, the coach can be credited for it, but if its only one line out of four, that praise doesn't go far.
When I spoke of Grigs, I was talking about his future development. I am not confident that Lindy develops players well. For quick examples, see the slumps that Vanek, Stafford, and now Myers, have been prone to having. Most players go thru slumps, but I am not convinced they come in the same frequency of some of the Sabres that Ruff has had in the last 10 years.