The other day I was thinking about Jake's decision to send Rachel in to kill Tom. It was so sad to realize that after all those battles, near-death experiences, bursts of optimism, and impossible odds, Jake was never able to fulfill his initial reason of fighting the Yeerk Invasion: Saving his brother Tom. Jake pretty much knew that this was a suicide mission for Rachel. He also knew that he had signed Tom's death warrant. From a tactical standpoint, I believe he sent in Rachel to cause confusion so that he could use the Pool Ship to either destroy or incapacitate the Blade Ship so that it didn't make its way into Z-Space. On a more personal level, I think he just wanted Tom to finally be free from the yeerks. Ideally, Jake wanted to free him from the Yeerks by saving him but near the end, he realized he wasn't going to be able to Kandrona starve the yeerk (especially since Tom had morphing powers too). Therefore, Jake's only choice was to end his brother's suffering by killing him and the yeerk. Using Rachel is also a great blow because she is another member of his family. (Although throughout the whole series, I never once recall her ever having any sympathy for Tom, her cousin...but I chalked it up to her being blood thirsty.)
I don't have a brother but if my father was a controller and in Tom's shoes, and I was in Jake's shoes, I don't think I could have given the order to kill him. I especially probably could not have used another family member, no matter how appropriate they were for the job. Even though my decision would be impractical, I know that at least he would be alive and that someday, someway, no matter how improbable, I might finally be able to rescue him. However, if he is dead, then there would be no rescue per say. (I would still feel bad that his suffering would now have to continue all alone in a desolate part of the galaxy.)
The only thing I could think of would be to switch places with Rachel and travel with him aboard the bladeship and demorph and remorph every two hours till I saw an opening to take down the other yeerks.
A really sad thing I noticed when rereading the series was that in an earlier book, Cassie told Jake not to worry and that someday they would save Tom. It was so sad knowing that that was a lie.