Blocking toxic relatives from calling.

My elderly mother has early onset dementia but is very independent and has a strong codependent personality. There are days when she can't take care of herself because of her rheumatoid arthritis but will answer calls from toxic family members who only want to dump their problems on her and ask for money. She will immediately take on their problems adding to her anxiety, depression and then eventually anxiety attacks. I recently mentioned this to my therapist when I told her I was tired of dealing with her emotional problems caused by these people. They get her worked up, she falls apart and my wife and I have to pick up the pieces. My therapist mentioned blocking their numbers for everyone's mental health and because it is my home and I should be able to set that boundary. My question is this, has anyone else faced a situation like mine and was there a resolution other than the one I was suggested? I'm asking because one of those people is my father and he's the worst one of the bunch but has never helped out with mom.