Do mental health checks on all household members of anyone trying to purchase a gun, before the sell is approved.

How many mass shootings could be prevented if the family members of the gun owners had been checked out before the sale of the gun was approved? I present the idea that ALL household members have a mental health check before any household member is allowed to purchase any firearm. Simply keeping the firearm in a secure location when there is a dangerous individual in the household is no t enough when the dangerous individual can simply take the firearm and use it to inflict considerable damage to themselves and others.