Advice on what to do with Marching Band?

First a little bit of background: I'm in high school and I've been playing drums for 6 years. I've played in Percussion Ensemble, Jazz Band, Concert Band, and Marching, pretty much everything you can try out lol (Piano included). I'm section leader at my school and since 10th grade (Fall of 09) I've been involved with the marching band. Probably the best thing I've ever decided to do to improve my playing. The first season was magic, I saw a major increase in my skills from playing with one of the senior percussionists at my school. I played last year and sort of ended up in an unofficial leadership position.

The problem: This coming school year, my brother and I will be employed as seniors, and we most likely won't able to participate. That's two out of three of the main marching drummers gone. We have a small marching band: 25 instrumentalists and 6 guard members.

Now, in 10th grade we had no desire to be in marching band, but the director made it clear that he needed two drummers, so we joined mid-season and liked it. We've had a marching band that competes in the Atlantic Coast Championship (Virginia to NJ/Pennsylvania) and managed to place in the top 20 every year despite the shrinking program. The director has done everything you can imagine to keep the marching band going at our school (he teaches Guitar, Concert Band, Orchestra, Percussion Ensemble and Jazz and Marching Band afterschool). Really hardworking guy. Well I'm not sure what to do to assist the Percussion section this coming season. If I absolutely wanted to, I could try to stay in Marching Band, but that would be juggling a job, AP classes, Tae Kwon Do, and college applications. It would be rough. Especially considering that my grades have dropped to a borderline 3.0 this year. I'd need all A's and B's to raise my grades to what I need for the college I want.

I don't want the percussion to be left with 7 pit and 1 senior marcher. Now the director is still trying to get my brother and I to join, even though he knows the employment situation. He thinks we'll be able to balance it, but I'm not entirely sure that I could. In addition to that, last year, I wasn't entirely pressed to join, but we had a percussion coach who had gone through the whole DCI thing and he was a phenominal teacher. In fact, I'll probably be getting lessons from him this summer, regardless of what happens. Seems like we're leaving the group hanging though since we are 2 out 4 seniors left, but I'm not purposely trying to hop out of the program, there's just no manpower.

I'm still doing Concert and Jazz Band and going to football games to play snare and do pep songs, I just can't do this one time consuming thing (Marching Band). Advice on what action to take here?