In the end all he needs is his brain... there happens to be another genius who survived the war, albeit a bit incomplete.
That's true, although if his body is not completely immune to the effects of aging, I'm not certain his brain would be. Although when speaking to him, he doesn't exactly give me the impression as someone whose brain has been hit by the negative effects growing old can have in that area. And in any case, he does at least sound confident that he still has enough time to carry out his plans.
Realistically immortality can be achieved to a certain extent by finding and removing part or all of the TERC gene/aging gene. Genetic alterations=the future of man. This kind of tech is a few hundred years away though.
To be fair, in the Fallout setting, prewar scientists were evidently able to engineer FEV and create some seemingly unlikely creatures through gene splicing, so I could see the technology to do something like that being developed in Fallout. However, prewar scientists seemed more interested in using their knowledge of genetics to find new ways to kill people than anything, and in any case, the nuclear war that largely obliterated prewar civilization turned out to be a slight setback in scientific development, so unless such technologies already existed before the war, I can't see Mr, House using it to extend his life span any more than he already has, and if he did have such technology, I'd say he would have used it instead of cryogenically freezing himself.