[Honza]

Ouch!
Sounds serious. There is almost too many things that can be done to help, its a matter of finding the right solution.
I think its important that your fiance surrenders themself to a higher power to look after them. In other words to surrender to God or Christ.
Also you could go to see the local vicar or have them come to you to recieve a blessing, if they are not christened you could ask for them to be christened.
There is a flower remedy from the Bach Flower Remedies which is for the protection from negativity/hate/evil. This flower remedy is 'Holly' from the holly bush. Your fiance could start taking that. In the same vein there is a Bach Flower 'Rescue Remedy' which is essential in emergencies. The remedies can be bought in health food shops and some chemists.
Those are the best things I can think of.

Godbless, Honza.