Can you remove the slider from the snowmobile in order to perform the repair???
That's probably the route you're going to have to take in order to avoid the potential of damaging those circuits unless you have a true square-wave power source like Miller Dynasty that doesn't need HF to weld Aluminum... However, I would opt to remove the slider if at all possible in the first place ;)

If your friend's machine is an older model power source that uses HF to weld Aluminum, and you cannot just as easily remove the slider as compared to the DPM unit and the Ignition circuitry combined with any other unshielded electrical/electronic components or microprocessors, then you should consider which option would be more logical, less time consuming and cost effective. To answer your question: More than likely there can be some damage...Exactly where - is not something I would gamble on finding out the hard way so, don't take any chances.

Respectfully,
Henry