Hello 'french' - I'm confused.
In your first post you advise that you have no further information on Alexander French, yet you have a photo of his wife and daughters gravestone a and you know where they died.
I'll leave this thread until you can advise what information you have and what you need.
There is only one marriage for an Alexander French in all of Scotland between 1900 and the date of his wifes Rachels death.
Regards, Steve :O(