Unless the by-laws provide otherwise, attending a board meeting by telephone is allowable, but voting by proxy at a board meeting is not allowed. If you have further questions, you should consult your attorney.
Disclaimer: This answer is provided for informational purposes only, does not constitute legal advice, and does not create an attorney-client relationship. Actual legal advice can only be provided after completing a comprehensive consultation in which all of the relevant facts are discussed and reviewed.
The Association has Bylaws which spell out the rules for the board to follow and how they conduct meetings. Typical Bylaws allow telephonic meetings in lieu of face-to-face meetings. Also the topic of giving someone your proxy to vote for you is usually described there as well.
This is not intended to be giving legal advice and this topic can be a complex area where the advice of an attorney should be obtained.