My wifes sister has in the last 6 months moved to the USA, with her filipino daughter, to be with her husband who has joint USA and Italian citizenship.

Is it possible for her to come to the UK without her husband but with her daughter using her husbands italian(EEC) citizenship? Would she be able to travel here without her husband and have the right to work?....or could she travel here with her husband and have the right to work?