This happened to a friend of mine who’s a software engineer at a Silicon Valley company. He either gets a month to spend looking for jobs, or follow through with the pip.
That depends a lot on why exactly your friend is on a pip. However, offering "a month to look" doesn't sound good. You friend needs to carefully examine the situation and fully understand the reasons why he is on a pip. Even if that's uncomfortable.
If he has no idea what's happening and why, than he should go with the "look" option. If he knows exactly what the problem is, he needs to come up with an actionable plan that has a credible chance of addressing the problem. This need to include a significant & obvious change in behavior, things like "I'm just going to try harder" will not work.