Gillette Sensor and Sensor Excel were excellent razor systems. I used them for years and if I hadn't lost the handle after I passed to the next big thing (Mach 3) I would probably still using it.
I understand your dad, at a certain age people don't want to change their routines or further complicate things, especially things that they don't care about.
Once I gifted my dad a can of Proraso foam and a bottle of Aqua Velva because in his late 80's he was dry shaving with a cheap Bic disposable and no aftershave. Years later I've found in his bathroom both the can and the AS still like new, except the can was rusty at the bottom. It was a little sad at the moment but growing older I discovered I don't like to be bothered by my daughters when they try to make me change some habits of mine or try to "convert" me to something else.
I understand your dad, at a certain age people don't want to change their routines or further complicate things, especially things that they don't care about.
Once I gifted my dad a can of Proraso foam and a bottle of Aqua Velva because in his late 80's he was dry shaving with a cheap Bic disposable and no aftershave. Years later I've found in his bathroom both the can and the AS still like new, except the can was rusty at the bottom. It was a little sad at the moment but growing older I discovered I don't like to be bothered by my daughters when they try to make me change some habits of mine or try to "convert" me to something else.