It sounds like you have done all the things anyone can do to try and get him help, you might have the sister try again to get a CIT team to come again while he is home to try and check on him but unless he does something to get picked up, his sister or someone else in his family may need to go a legal route to get him help. It is very hard to convince someone in a manic state that something is wrong with them and that they need help.