The match was the culmination of a week of games arranged by Lydbrook Football Club to raise funds for the family of Mr Brain who died from cancer earlier this year.
All the top Forest clubs took part in the competition - organised on a knock-out basis - which cuminated in Saturday's final played in sizzling heat.
The match attracted a crowd of around 300 and they watched Cinderford turn on the style to take advantage of every Lydney mistake.
"Lydney were very competitive and the score did not reflect their contribution," said Lydbrook's Wayne Lewis. "They tried really hard but Cinderford punished every single error they made."
The score was 3 - 0 at half-time and earlier Lydney had a penalty well saved by John Rendall.
Cinderford, who play several leagues higher than Lydney, took control in the second half and won comfortably with goals by Sean Davies and Rob Colwell (two each), Jody Bevan, Dave Toomey, Adie Harris and Chris Lewis.
Premier division referee Kevin Hawkes stopped play as necessary to allow the players to refresh themselves.
The trophy was presented by Alan's son, Luke Brain.
"It was a very successful occasion and we would like to thank everyone who helped," said Mr Lewis.