Involve the Whole Family When Possible
Chances are you are reading this because you’ve already tried to get your folks to pare down before it’s time to leave the family home. Even though you’re tempted, it's generally not a good idea to "help" them by sorting through their stuff and packing it out the door, when they're not around. If you try to make a major decision about your folk’s belongings, chances are you're going to shoot yourself in the foot.
As a goodwill effort to prevent emotional flare-ups, and ensure a more peaceful resolution, schedule a meeting with the whole family, if possible, to discuss an exit strategy several months before the ideal move-out date. (If you can't assemble in one place, do it by phone or conference call.) Propose and negotiate some talking points and send them to everyone before the meeting: Under what circumstances will you call each other to consult about "keep or donate" decisions? When and how will you involve the person who's moving? What key possessions would you and your other family members like to keep in the family?
Encourage the person who's moving to actively participate in decisions. Your parent should be able to pick what they keep, unless they truly cannot make these types of decisions for themselves and have an appointed guardian. It's best to let them take their own furniture if they want to, -- they know what makes them most comfortable, and comfort and familiarity often count for more than aesthetics. If you don’t feel you have the ability to effectively communicate with family members, suggest hiring a professional with senior moving service experience to help. It’s well worth the cost and gets you off the hook.