Relative indeed died, or passed on (7)
I believe the answer is:
relayed
'passed on' is the definition.
(to relay something is to spread or pass it on)
'relative indeed died' is the wordplay.
'relative' becomes 'rel' (mathematical abbreviation).
'indeed' becomes 'aye' (I've seen this before).
'died' becomes 'd' (abbreviation next to the year of someone's death).
'rel'+'aye'+'d'='RELAYED'
'or' acts as a link.
(Other definitions for relayed that I've seen before include "Passed on from hand to hand, station to station etc" , "Broadcast; passed on" , "Transmitted along" , "Passed along" , "Layered (anag.)" .)