Bus 635 leaves from the airport (easy to find, just follow the signs) every 20 min, here's the schedule: http://is.gd/bKYvJh Takes around 20 min to Freising.

However it does not go to Krankenhaus but to main train station. You can of course change to another bus but I prefer a nice 15 min walk to the hotel: http://is.gd/KNFkcR If you have luggage taxi might be an easier and faster option. Costs around the same as train to Munich and takes 10 min.

Freising is a beautiful little town, highly recommended! I stay there every time I have overnight in MUC. If you have time go to the Weihenstephaner brewery (the oldest in the world!) and have a drink, or just stroll along the main street. If you feel to tired to leave the hotel there's a quite good pool / sauna / spa there.