There are several dementia stages that the person will experience as their condition evolves. The biggest issue with these stages is that they will 
start to deprive the individual of their ability to get things done independently and this is going to be very frustrating. Once the condition worsens, the stages will get to a point that will make the process of doing the most basic things almost impossible to handle alone.
The initial dementia stages usually involve some mild memory loss and disorientation issues. This means that the person is going to continue to be able to carry on with their activities and they will be fully independent. Then, once the middle stage of the condition is reached, the person is going to have a harder time being able to remember things and they might feel disoriented when trying to go to locations they have already visited before.
Out of all stages of dementia, the third is the most difficult to handle because the person is going to start forgetting very basic things about their own lives and they might even feel disoriented and lost in their own homes. The final stage will involve loss of motor functions and difficulty doing the simplest things such a putting on clothes and eating.