Dad showing early signs of dementia or alzheimers?

im only 27 years old, do NOT have the means to support my mom if my dad were to actually have one of these. what exactly would happen to him? to my mom? my mom can't work, who would take care of my dad? where would he go if we couldnt afford anyplace? how does my mom take care of him when shes taking care of 4 elderly grandparents? it just seems impossible.