If you are already treating this person, then there is no need to stop - vascular dementia is not a contra-indication. Treat them as you have been, just be aware of the changes that may take place in the future - you may need to adjust your sessions so that you are just doing relaxation rather than 'treatment'. There will, sadly, come a time when you can do no more. I watched this dread disease destroy a man I had known and treated for many years.