If I had a stroke and developed cognitive impairment and problem behaviors, I would demand my children put me in an Assisted Living Facility, and if I met the requirements, a Nursing Home. There's a difference between the two and it's important to know. Most likely, your friend's father will not qualify for a Nursing Facility yet. I would never wish to burden anyone with my problems.
It doesn't matter what outsiders tell you- their opinions don't matter if they're not doing anything. They're not walking in the family's shoes. At the end of the day, it's the people who live with him and care for him that needs the most support.
If you want to know the process, hit me up.