No, the c-decay theory is bunk because c changing by more than a percent means Earth frying as the relationship between matter and energy changes and thus the sun's fusion output steadily decreases over time.
These guys can moan all they want. They cannot evade the fact that the most fundamental constant of science hasn't changed without a significant inpact on the universe, or do they think lightspeed changing wouldn't have any effect on fusion?
All of which goes to show you haven't a clue about the thing. Best you learn before you declare....