How can a Muslim residing in Switzerland avoid ritual impurity in his home, which is inhabited by his wife and her two dogs, and what is the ruling on his clothes being touched by the dogs?

It is forbidden to keep a dog except for purposes permitted by Islamic law, such as hunting or guarding. One must be careful to avoid its impurity by staying away from close contact with it and not allowing it to enter the dwelling. If a dog accidentally touches your garment or body, and no wetness from it transfers to you, then there is no issue. However, if wetness from its saliva transfers to you, the area of impurity must be washed seven times, one of which is with earth. As for dog hair touching your garment or body, if the hair is dry, or if the wetness is only on the garment or body and not on the hair itself, then impurity is not transferred, based on the opinion that dog hair is pure.