We also ensure that all work is contained to specific areas to minimize disruption and mess in other parts of the home.

I would have done it even after family if not too much of a downgrade or disruption - but somehow it never occurred to me back then.

Life events can certainly disrupt finances, but at the end of the day, you’re running a business and need to protect your assets.Since you've already had multiple conversations and haven’t seen meaningful progress, moving forward with the formal process, like a 3-day notice, makes sense.

This industry is ripe for disruption. 

Wrongfully terminating individuals not only disrupts their lives and livelihoods but also reflects a lack of respect for their rights as employees.

Quote from @V.G Jason: Disrupt the actual real estate agent and closing process.Remove agents and loan originators; they prey on emotion.

My suggestions would be doing a fully detached ADU on a side of the lot where the people staying in it can exit without disrupting the front house/main house.

This is a major disruption to people sleep and lives.  2. 

@Eric Samuels If you parents have to leave due to disruptive conditions the landlord fails to address, then in some states that is know as "Constructive eviction"  In other words your parents leaving is essentially considered an illegal eviction by the landlord.Your parents could be due damages for having to leave.

This prohibition includes, but is not limited to, loud noises, loud music, noxious or unpleasant odors, and disruptive behavior or actions."