Any change to the timestamps for nLocktime and the block header will require a hard fork. Given that this is a long term problem, it is not particularly urgent right now to fix this.
And hardforks tend to break nlocktimed transactoins, potentially forever destroying their funds...
It's really inadvisable to use locktimes set in the far future. Though everyone working on the Bitcoin project works hard to not invalidate existing transactions, we don't know what new challenges the future may bring-- and the Bitcoin of 2110 might well not accept a signed transaction drafted today.
For your example it's far better to just store the private key needed to spend the funds.. you'll need that anyways in any case... (unless he intends to just give his funds to miners in the far future...)