I know as an adult it is very difficult to watch a child spell a word wrong but it is for their benefit. We think we are helping them but we are not. They will never learn how to work on their own if they never have to do anything on their own. Let them experiment with the spelling, if a silent letter is not there, it's alright. They will get it. In fact they will be better off if they make that discovery themselves.
This is coming from someone who has spent a lot of time in many different kindergarten classrooms where too many kids are wanting their hands held in sounding out words. It doesn't matter if it is just a random bunch of letters just as long as they have spent the time to sound out the word. The connections will be made and they will be better off if they are allowed to experiment. It is part of the developmental process. They are capable of it too, but as adults we contribute to them thinking they are incapable of doing it. There are always excepts to the rule, but they are very few in comparison to the vast majority (and even then the exceptions need the chance to experiment and grow too).