Deryck Whibley has claimed he was “groomed” by his former manager, who “pressured” him into a sexual relationship. The Sum 41 frontman was 16 when he met Greig Nori, who was 34, and while they shared a “special connection” on a creative level, he has alleged he was sexually and verbally abused by the Treble Charger singer over the years. In his new memoir ‘Walking Disaster: My Life Through Heaven and Hell’, the Los Angeles Times newspaper reports Deryck tells how he met Nori at a Treble Charger show and he invited him to watch his band perform, leading to the older musician becoming a mentor a…