While I, uh, don't necessarily support the advice given by your parent comments ... this was literally the top result of a Google search for [a parent's house being seized because their child was arrested for drug possession]: http://www.cnn.com/2014/09/03/us/philadelphia-drug-bust-hous...
Choice quotation: "In 1988, Paul and Ruth Derbacher, a couple in their eighties, lost their Connecticut home after police raided their house and arrested their twenty-two year old grandson for selling drugs. Police found $50,000 worth of marijuana and cocaine in the house. The grandson was convicted of drug charges and sentenced to prison. The Derbachers were also charged with drug possession and were placed on probation. Prosecutors claimed the drugs were kept in plain view and that the Derbachers must have been aware of their grandson’s illicit activities. Although the Derbachers fought the seizure of their home, they ultimately reached a settlement agreement. The house was sold, and the couple split the proceeds of the sale with the government."
Most of the top results are about that case. Maybe it's misleading or simply inaccurate. However, check out this webpage (the fourth result) which offers legal advice: http://www.criminaldefenselawyer.com/resources/if-my-kid-arr...
Choice quotation: "In 1988, Paul and Ruth Derbacher, a couple in their eighties, lost their Connecticut home after police raided their house and arrested their twenty-two year old grandson for selling drugs. Police found $50,000 worth of marijuana and cocaine in the house. The grandson was convicted of drug charges and sentenced to prison. The Derbachers were also charged with drug possession and were placed on probation. Prosecutors claimed the drugs were kept in plain view and that the Derbachers must have been aware of their grandson’s illicit activities. Although the Derbachers fought the seizure of their home, they ultimately reached a settlement agreement. The house was sold, and the couple split the proceeds of the sale with the government."