What should i do??????

i have a friend but she has a guinea pig that has over grown claws and she doesn't clean her shavings every day and she doesn't have any hay for bedding and she doesn't go out in her run everyday and i think she is depressed because she has lost her sister (that she said was mine but hers cause she only like one the one that is alive but sammy(my one) died and i don't no why! but i think she died because my friend did look after her right ;( i miss her should i try and tell her or should i call someone like: the RSPCA or PDSA???????? help!!