Yep, depends on how bad you think the coaching philosophy is.
If you'd just do things differently, or you think the coach is being a bit too harsh on the kids, I wouldn't say anything.
If you think the coach is being unsafe, unduly nasty, or even abusive, I'd firstly ask the coach why they're doing what they are. Assistant coaching teaches you how to be a better coach (in theory), so you're supposed to ask the coaches why they're making decisions anyway. Even if you know you'll be dissatisfied with the answer, ask, because the next step is to quietly speak to the head coach/supervisor/office and let them know what you're thinking. You don't want to look like you're accusing the coach of anything without speaking to them first.
Would you be able to elaborate on what the coach is doing that you dislike? It's hard to give more specific advice otherwise.