If in the saff during congregational salah someone next to me standing is wearing a pig skin leather jacket and this jacket does touch my clothes during the salah, is my salah invalidated? And what if it does my skin?
Firstly, you should not put yourself into unnecessary difficulty and doubts by assuming the jacket to be made from pig skin.
There is a principle in Islamic jurisprudence which is:
“Certainty is not lifted by a doubt.” (Al Ashbah Wan Nadhair p.60)
Regarding your question, if the jacket is really made out of pig skin, then your clothes would only become impure if there is moisture on it. Otherwise, your clothes will remain pure. (Fatawa Hindiyyah p.48 v.1)
Finally, if the impurity is more than a Dirham then your Salah would be invalidated. (Nurul Idaah p.51 –p.54)
Only Allah Knows Best
Mohammed Tosir Miah
Darul Ifta Birmingham