1. It's very rare to say or hear 'all things' these days. It mainly exists in a few idioms and slightly old-fashioned expressions. The correct modern-day usage is 'all the things'. 'Did you bring all the things that I asked for?' 2. Neither of those sentences is correct. A possible correct sentence might be: My mother is just as beautiful now as she was when she was young. In this sentence, 'just' means 'exactly' (as in 'just the same').

1. If 'things' is indefinite, say 'all things'. If 'things' is definite, say 'all the things'. In both cases you can just say 'everything'. 2. All three sentences are incorrect. They should be "My mother is as beautiful as she was when she was young" and "My mother is beautiful, (just) as she was when she was young" (I'll treat the last two sentences as one). They're not the same. The first sentence means that your mother is no less beautiful now than when she was young ie. she is equally beautiful as her younger self. It doesn't actually say if she's beautiful or not, just that she's no more or less beautiful than before. The second sentence means that your mother is beautiful now and she was also beautiful when she was young. She's not necessarily as beautiful as when she was young, but it's implied. That implication is much stronger when 'just' is added.

"All things" may have the following uses: 1. All things bright and beautiful; All creatures great and small; All things wise and wonderful; The Lord God made them all. It is a well-known hymn. 2. All things considered, I am going to ask him to resign from the Cabinet. 3. "All Things Must Pass" is as much the name of George Harrison's celebrated album as it is a statement of his philosophy. 4. It is used in expressions such as "all things human and divine" and "all things sacred and profane".

1. When someone says "all things", they could have also said "everything which is", or "all things which are". "I like everything which is beautiful." "I like all things which are beautiful." "I like all things beautiful." I can't think of another situation when I would say "all things", but one might exist. 2. All three of the sentences are wrong, the three sentences I think you want are: "My mother is just as beautiful as when she was young." "My mother is beautiful, just as she was when she was young." "My mother is as beautiful as when she was young." The first and third are different from the second in meaning. The first and third ones mean her beauty is equal to her beauty when she was young. The second one means she is beautiful now, and was beautiful when she was young, but not necessarily equally beautiful.