Small Wood house for Eldery widow

For an elderly widow, of over 80 years old, i want to build a wood room next to her old house, as a present for Easter 2020. She needs it a lot for certain reasons, and can not afford it herself. She is a diabetic and has a pension under 150$ a month. Let's help her! I will personally do for free all carpentry, but i need money for materials, wood, cement, gravel, nails, etc. I will post pics when it is done!