Measures family member self-efficacy in medical decision-making on behalf of a loved one. This scale has two versions, one for conscious and one for unconscious loved ones, which we will use accordingly. Thirteen items are measured on a 0-5 Likert scale with 1 being "cannot do at all" and 5 being "certain I can do." Higher scores indicate higher decision making self-efficacy.

Questions adapted from an 82-item questionnaire that measures advance care planning engagement in terms of knowledge, contemplation, self-efficacy and readiness. We include 10 questions from the measure. We used a mean imputation approach. All available data were included to create an average 5-point Likert score.

Measures perception of the usefulness of a decision support tool in preparing respondent for decision-making. Responses are on a Likert scale of 1-5 with one being "not at all" and five being " a great deal." Items are summed for scoring. A higher score indicates a higher level of perceived helpfulness in preparing for decision-making.

We adapted 9 items from the 17-item Advance Care Planning for Surrogates survey. Response options are on a 5-point Likert scale. We will calculate a summary score, with higher scores indicates a higher level of engagement.

Six questions to assess family members' knowledge about dementia were developed for this pilot study. All questions are true/false. Each correct answer will be coded as 1, each incorrect answer will be scored as 0. Higher scores indicate more knowledge.