Forbes opened the scoring on 39 minutes with a half volley from 25 yards, before Waddecar and Wisdom extended the advantage in the second half.
Colleries centre back Kieran Nolan was shown a straight red card with the score still at 0-0.
The win is Brig’s second of the season and lifts them up to 14th place in the Northern Premier League table.
Joey Collins made two changes from the XI that lost to South Shields on Saturday, with Forbes and returning captain Matt Lawlor coming in for Matt Dudley and Phil Doughty.
The hosts had the better of the early exchanges, Waddecar’s close range header well saved by Atherton ‘keeper Christopher Cheetham.
Lloyd Rigby was called into action on eight minutes as he caught Thomas Bentham’s strike, before doing the same against a Kieran Nolan shot on 21 minutes.
That was to be one of Nolan’s last actions of the game, as he was sent off eight minutes later for a late tackle on Wisdom.
That preceded a manic couple of minutes for the visitors, who were penalised for a backpass before Chris Marlow’s resultant shot curled narrowly over the bar.
Ryan White then came agonisingly close following a surging run on 35 minutes, with his effort going narrowly past the post.
Brig’s pressure then finally told on 39 minutes.
Danny Forbes received the ball just outside the area before unleashing an unstoppable half volley into the bottom corner.
Joey Collins’s side then quickly extended their advantage once the teams returned for the second half.
Waddecar shifted the ball onto his right foot in the area before driving it into the bottom left corner on 48 minutes.
Atherton almost found a way back into the game when a floated cross went over everyone and narrowly evaded the outstretched boot of Colleries substitute Jack Egan.
Wisdom then gave Brig a 3-0 lead on 62 minutes, his 25 yard screamer into the top corner providing a strong rival for goal of the night against Forbes.
From then on the home side controlled the game, with the only real danger coming from a Vincent Bailey free kick which whistled over Rigby’s crossbar.
Brig held on for the clean sheet and a 3-0 win, their second victory out of two at the Sir Tom Finney Stadium this season.