Hi... first of all, I'm sure that the jacket has some sort of finish on it, and that would have to be removed in order for any dye to actually do a good job of penetrating. In addition, dyes can react with certain finishes to create a bit of a "stickiness" that can occur, if you don't get all the finish off. Especially down in the seams and hard to get at places. And it's quite possible that you'd never get an even color, and there's also the issue of trying to put a sealer over it when you're done. All leathers are different, and can react differently to various situations. Some leathers are incredibly prone to dry out and become boardy if too much of a dye is applied. Some leathers that would not be a problem. With some leathers, removing a finish with acetone can be quite successful, and with others, it's about impossible. Some leathers can be re colored by mixing a bit of dye with a leather conditioner. Some leathers just won't accept it at all. Some leathers will accept dye readily once the finish is removed, and some won't. Anyway, I won't bore you with more "if's and maybe's". You might get away with it, and you might not. I'm just more familiar with the situations that didn't work, I guess. Thanks for asking!
Kevin