Assuming House ending was canon ending,how many time do you think he has left? You can see in his chamber that he is in a very delicate state and cannot even leave his chamber without consequences.
I think he would die in 50 years f luck,if 200 years left him like that,

What do you think?

he was in a casino that was locked up heavily armored by securatrons and for the most part it was a hidden room, yeh I think he could live for 200 years

The chamber he resides in protects him from the outside world so that nothing can harm him. He could probably live forever as long as he is in that chamber.

Its important to note the ending info only goes out a few years so no matter what ending is canon it only effects new vegas for about 20-30 years after the game.

As for how long house could live... he himself expects at least 100 or more years of life and being how smart he is hes likely 100% right on that projection.