It may be of help to see if there are other problems. Many wind bands do NOT tune properly. Bad intonation will kill even the best players. if this is the case - offer to tune the band, learn the common prolems of each instrument group and help to fix or compensate. There is no call in a wind band to play every note. The parts are covered by multiple players and they can alternate to thin the sound out a bit and keep the chops fresh. Another help may be to push YOUR tuning slide in 1/4 to 1/2 of an inch and relax when playing. Many players that I work with play VERY tensly!