Tense questions

0Hi, I have three questions on tenses.02br
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001. How are they different? The mixing of a present and present continuous is what troubles me.02br
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00He frowns, while he looks very embarrassed.02br
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00He is frowning, while he is looking very embarrassed.02br
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00He is frowning, while he looks very embarrassed.02br
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00He frowns, while he is lookng very embarrassed. 02br
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002. I think it has been said a present tense indicates a habit and a present continuous on-going action, but I feel that might not help much to English learners to help them to understand what a sentence is telling them fully.02br
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00He plays chess. -- Does this indicates a habit? Can it also imply he is playing chess now -- on-going action?02br
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00He is playing chess -- I think many will say this indicates an on-going action.02br
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003. Should I change the tense here? Mingling a past with present is what gives me trouble.02br
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00He thought it was important to help her and that is why he is sending her the money now.02br
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00Should I change it to?02br
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00He thought it was importnat to help her and that was why he decided to send her money.-- but this lacks the present action part: What he is doing now. 02br
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00He thought it was important to help her and that is why he has decided to send her money now.0-