From a friend perspective, ok, give him the ultimatum/'one last chance' (even though you've pretty much already done that. From a bandleader/management perspective - quantify it. 'You need to do such and such on these songs, work on x, etc. Do you need a click-track? No shame in that. Do you need extra time with me to work on stuff? Cool. ' Give him everything he needs to counter his excuses. aka, enough rope to hang himself.