^^ But she stated it is affecting him and their two year relationship.
If mom lives with him now, she'll be living with them after the honeymoon. If he cosigns on a loan after a wedding, her credit will jacked up. If somebody needs to be bailed out of jail, it'll be coming out of their emergency fund. If their kids want to visit aunt, they may end up around some unsavory characters if their is still some hint of drug activity going on.
Now none of that is happening now of course, but the advice is based on the fact that most believe she is dating with the purpose of finding a lifelong mate. Despite the grim marriage stats ,most want to marry. So the question is after witnessing two years of this pattern, is it worth putting more years into the relationship or thinking about the next step engagement with him given the entire situation. When you marry a man you marry into his family.