Yes, unfortunately, to both of your questions.
In order to enter a home, the police need either a warrant or an exception to the warrant requirement. The most common exception is the consent of the home owner, but there are others. Another would be under an emergency situation and to prevent the imminent destruction of evidence. A 911 call would constitute such an emergency.
If your daughter and boyfriend's rights were violated because the police were lying about the call, if they want to fight the criminal case, their lawyers would be able to move for a suppression hearing to challenge the basis for the search and whether the police overstepped their authority by not having a warrant. If your daughter won the hearing, anything the police improperly recovered due to an illegal search and seizure would be suppressed. That is, it could not be used as evidence against them. That would mean that if their only charges were the drug charges, the case would have to be dismissed. If your daughter loses the hearing, the case would go on.
Sometimes when the police can't tell from the facts and circumstances who the owner of the contraband is, when they come into a house with multiple people in it, they charge everyone in the house with possession. They can do this under the theory of constructive possession. That is, your daughter and her boyfriend were there. Either of them could have gotten access to the drugs and taken them into their custody and control, so both could be charged.
While her boyfriend said they were his, the police and prosecutor do not have to believe that if they think under the facts and circumstances that the marijuana was to be shared between them. I have had cases where one of the co-defendants in a situation like this got his case dismissed at arraignments, and others where the prosecutor went forward against both parties. It all depends on the facts and circumstances and what the prosecutor feels he can prove beyond a reasonable doubt.