How can i destroy these ship class?

[Atrocities]

HdS, I would say at this point that your best option would be to avoid his fleet and target his planets directly. His engine damaging weapons is useless against planetary weapon platforms so be sure to beef up all of your planets with lots of WP's and satellites.

Also a nifty trick is to still use mines in the late game. In most cases they may not suspect it and if the fleet has no minesweepers you might get a few kills.

But I would just go after his planets now and avoid him in combat unless you have a 10 to 1 advantage.