Thanks for the reply guys!
I am simply using the command option to insert the multileader.
(command "_.MLeader" pt1 pt2)
(while (> (getvar "cmdactive") 1) (command ""))
(setq emleader (entlast))
(setq eblock (entnext emleader)) ; return nil.
I know the last line is not correct, I am looking to just get extent of the block that is drawn with multileader. The MleaderStyle content type is block. I believe I can use that block name to insert in the drawing and get the extent but the user can make changes to the block scale in the multileaderstyle and therefore, I assume its best to select the block that is drawn with multileader (which will have all settings applied e.g. scale) and get its extent. I will be adding the same block multiple times vertically or horizontally.
P.S. (vlax-ename->vla-object (cdar (entget (entlast)))) gives me the mleader and not the block.
Thank you!