This could go a lot of different ways...
First off it swelled enough to crack the lower unit then it for sure swelled enough to damage seals... Which were already damaged enough to let the water in. Then you have rust on the bearings. Then you have potential movement or swelling of bearing seats due to swelling and cracking. There are some very tight tolerances at risk in that unit. What I'm trying to say is: you may be able to weld the crack, change the oil, and ride to town. It may last 10 years, it may last 10 days, it may last 10 minutes. What you don't want to get into is welding the crack, changing the seals, changing the oil, replacing rusted bearings, etc to the tune of being more expensive than a lower unit. Also... I have never had one break at a convenient time.