The Bylaw is available online
Section 19.2 Waiting Period, Players.
Except as provided in Section 19.5, a person is not eligible for election in the player category if he or she has played in a professional or international hockey game(which terms shall not be considered to include games played only or primarily for charitable or recreational purposes, or for any other limited purpose that the Chair determines, in his or her discretion, should not disqualify for nomination a person otherwise eligible) during any of the three (3) playing seasons immediately prior to his or her election.
Section 19.5 Elimination of Waiting Period.
Any person who, by reason of grave or terminal illness or injury, is not expected to survive until the next annual ceremony at which candidates elected to Honoured Membership may be inducted, may be nominated by a member of the Selection Committee at any time and the deadline for nominations in Section 20.2 and the provisions of Section 20.4 shall not apply to any such candidate. In addition, the Selection Committee, by an affirmative vote of at least three quarters of the members thereof present and voting at a duly convened meeting approved by the Board pursuant to Paragraph 22.1(a), may, in its discretion, eliminate the three (3)-year waiting period referred to in either of Sections 19.2 or 19.4 in respect of such candidate and such candidate shall then be eligible for election to Honoured Membership.
So as it's written, they would have to amend the bylaw to induct Jagr early. I don't think they can reasonably call Czech league games "charitable or recreational".
The elimination period is just for illness, but it looks like there's enough wiggle room with the wording they could induct a deceased member before the three years is up.