the difference is he enabled his mom's "better life" so that's likely why she gave him control over the estate and asked it be split fairly, which for the record is not the same as equally. If she had the foresight to make a will in the first place with the intention of having her children all get an even share, she could have done that. My take is she did it this way knowing that her son stepped up enabled her better lifestyle in the interim and let him decide whats fair. For the record, given the appreciation in value, the son is actually taking less than he is truly entitled, by not factoring in the capital appreciation of his 135k contribution.