Much easier to stay motivated with 25% of a growing company vs a larger share in a failing company. Hopefully she negotiated some better terms, and has some protection from being pushed out and diluted. If so, this could end up being a very lucrative first business for her even if she doesn't make her earn out.
That depends on ones frame of mind, doesn't it? If you consider that buy-in a failure - and who in that situation wouldn't? - Would you really be able to push on after that? Would you really want to?
If she maintains control, then sure - that might work, depending on how large amounts of sale she can gain from this move. But 25% doesn't smell like control to me.