My son is a neat freak, almost obsessive about it. his girlfriend has a bull mastiff, slobbers all over?

They have been dating for a couple of months and it seems to be getting pretty serious. Any mastiff owners out there who have dealt with these type issues in a relationship? Is there any way for a relationship like this to work out. I cannot see it working at all. They are not living together and he has only met the dog once. I would love some feedback on these issues.