Jacob is an $82-$year$-$old Red Deer man who has run several successful businesses throughout his life, and owns various pieces of equipment. Over the past few years, Jacob's son, Isaac, has noticed that Jacob's hearing is failing and he has had some fender benders. Isaac lives in Saskatchewan and depends on his brother, Joseph, to keep an eye on their father. On a visit to Red Deer, Isaac notices that his father's holiday trailer is gone from his yard. Isaac asks Joseph where the holiday trailer went and Joseph says that their father sold it to Joseph's friend, Mary, for $$100\mathrm{.}00.$ Isaac is concerned because the holiday trailer was worth about $$10,000\mathrm{.}00.$ Isaac takes Jacob to the doctor the next day and the doctor advises that Jacob has dementia and has lost mental capacity. The doctor invokes Jacob's enduring power of attorney, which names Isaac as the attorney.

Explain: $($a$)$ the legal claims that Isaac may bring against Joseph in relation to the sale of Jacob$$s trailer. $($b$)$ the legal claims that Isaac may bring against Mary in relation to the sale of Jacob$$s trailer. $($c$)$ why Isaac may choose not take any legal action.