Wait a minute, didn't she send him the damn holy axe or something? I might be remembering things wrong though but I vaguely remember she did something to help Wulf. So her sudden betrayal here due to "envy" and "neglect" by her family is still kinda sus.
Oh yeah, and I guess his name isn't Beowulf if their family name is Beo... so he's Wulf Beo using Western name order.