Singular.
The light troops thought ... that all was lost.—Palgrave
All was won on the one side, and all was lost on the other.—Bayne
Having done all that was just toward others.—Napier
Plural.
But the King's treatment of the great lords will be judged leniently by all who remember, etc.—Pearson.
When all were gone, fixing his eyes on the mace, etc.—Lingard
All who did not understand French were compelled, etc.—Mcmaster.
Somebody's else, or somebody else's?
426. The compounds somebody else, any one else, nobody else, etc., are treated as units, and the apostrophe is regularly added to the final word else instead of the first. Thackeray has the expression somebody's else, and Ford has nobody's else, but the regular usage is shown in the following selections:—