Active and inactive Clan members are treated the same during Clan Wars.

They can still be the targeted by enemy bases, and may receive donated clan troops.

However, because inactive Clan mates will not use their attacks, they are a potential liability, and will in no away help your Clan toward victory. Additionally, if you leave your village inactive during a war, you will not receive any bonus loot following a win.

Thus, you should encourage your clan mates to be active Clashers for optimal results.