Honestly speaking, as a council member volunteer, they have a responsibility to their role. It's like forum moderators -- if you don't do your job because you decided to jam pack your schedule with tournament stuff and not giving yourself some time to do what you signed up to do, then there is a problem and things may need to be addressed.
Any time I've ever seen something like this happen, be it a volunteer or someone's actual paid job, it resulted in them getting let go and/or replaced. I've seen it from anything ranging from volunteer firefighting work to school management team (think of like tech squad for school events) to actual jobs.
While we don't know the exact goings-on in the council voting process, they should've had time to at least look over community opinions on the matter and spectate some games. Or hell, watching various people who play live on Twitch or YouTube when they have downtime. I know what it is like to be a moderator, as I'm an admin in my own community server (not Pokemon related), and I've been a moderator for a popular game server in the past.
That being said, there REALLY should have been a heads up on their reason for full abstain ahead of the vote. Without any word of "Hey, this council member is extremely busy as this, this, this, and these are all taking up their free time" (even if it's just something simple and private like life stuff got in the way), it reflects on them FAR better than silence into full abstain. Like seriously, I don't even know this xavgb person, what they do for the council, or anything else like that. As far as I am concerned and aware of them, they're just another member of the council and a name on the voting board. I don't follow tournament results, or who's playing what, or who earned the most internet points for consistently placing high in whatever tournaments. The most I follow is evolving meta trends, OU council's decisions for action within the tier, and anything that affects Smogon-wide rulesets.