When you begin the process to secure the money you must be a joint owner on securities accounts so you both have to sign to withdraw funds. there are two benefits to this 1) the elder has the feeling of still having control over their money and (2 they can’t make withdraws without your permission. So when the neighbor or your brother comes by to borrower money for some bullshit emergency they cannot make the withdraw. Although you are a joint owner you will also need to be POA on this account at the same time. See Planning for capital gains