How old is the drummer?
OAN, it's really unfortunate that his father isn't teaching him responsibility, integrity, commitment, dependability or reliability.
Amen. Sounds like bad behavior is going to perpetuate for another generation...
That said, in my 15 years involved in worship ministry I've learned that there are two very important elements to most any thing that requires group participation:
communication
standards
Those two things are the most absent in a failing ministry and most present in a thriving ministry.
Just like our prayer life, communication on a team is a two-way street and vital in order for everyone on the team to be of one accord. For me, I use the phone, emails, Facebook and in-person means of communicating w/ the folks on my team and, sad to say, I still fail at getting them all the info that they need and they in turn fail to get me all the info that I might need, but I aim to always improve on it and extend grace when necessary as they do to me. We are leaps and bounds beyond where we've been as a team as a result.
And we should not be afraid of setting standards for those who are serving in the ministry. Just as we don't want some child molester watching over the kids in the nursery, we don't want a lazy or lacking or unsaved musician offering up their 'less than excellent' gift to God in worship. And the standard does not have to be pro quality, it just has to be right and non-offensive. For example, I don't care if someone can or can't play blazing guitar solos or wicked drum fills, but it's a big deal if they can't count to 3, 4 or 6 repeatedly and in-time without rushing or dragging on their instrument. I've had to speak to people, especially drummers who seem to have been blessed with an extra dose of adrenaline from birth, about the less-is-more concept when it comes to music.
Musical standards can be basic: play or sing the right notes, play in-time and at the right tempo, complete the song.
Finally, I feel that we always have to have the attitude that even if no one else will stand with us and worship God, we have to be willing to do it solo and with all our heart, mind, soul and strength. That, in my opinion, is the most important element of the music ministry. It's not our title, it's not our church, it's not our skills, but it's our willingness to worship God regardless.
Doing this is very frightening to those who don't get it and very attractive to those that do.
How do you deal with your current situation? I think you need to have some one-on-one meetings with people about their involvement. If they're serious, you set the standards and they have to be met or else. That way, it's not you telling them they can or can't play or be a part of the ministry, it's their own attitude, ability and motivation.
And pray, pray, pray...I've seen more things resolved through prayer than through all my trying.