According to the sources, the absence of Gopi in the marriage ceremony of Dileep, Kavya Madhavan held in Kochi was thanks to Nishal Chandra - the ex-husband of Kavya.
Gopi is the relative of Nishal Chandra and it was he who moved the proposal. Hence, Gopi was in a bind and seems to have felt it would be better if he skipped the wedding.
A few reports stated that the actor tried for a compromise between the estranged couples, Kavya and Nishal Chandra. But to no avail.