A gentle room-by-room plan. The hardest part is starting. Pick one room. Spend 90 minutes. Stop. Repeat next week.
0 of 9 rooms done. The goal is not to finish in a weekend. The goal is to make a decision about each thing in each room, one item at a time, without rushing yourself. A senior move manager (NASMM.org) charges $50-$125/hr if you want a calm professional helping.
For very sentimental items you cannot keep: photograph each one, write 1-2 sentences about it, and save it in a "memory book". You keep the meaning. The object can go to someone who will use it.