Well you need to read the by-laws of your condo association and see what they say about your rights and obligations as the president.  I am going to assume that the by-laws give you the right to bring an action against another board member that is breaching their fiduciary duty tot he condo association but you may need to hold a meeting and take a vote and/or have some other of the board members backing you on this. You may need to convene the board and ask him in a formal meeting with someone taking minutes about what is going on.   I do not know.  But I am sure that an attorney who deals in condo rights can help you.  Good luck.