Hello Beauthai,
Thanks for reaching out. As long as the optin was successful he should have been added. Otherwise he should have received an error message. Please let us know what he saw when attempting to subscribe.
To make your form appear everywhere you will need to add it to the sidebar that is appearing on your other pages. It sounds like you have one sidebar for your homepage, and another for other pages, so make sure you have published an optin form into all your sidebars. How your sidebars work depends on your theme, so it may be worth reaching out to your theme authors for further assistance with this.
Let us know what your friend in germany is receiving, and we will do out best to make sure we get everything working.
Regards,