Bonjour
<em>my oldest brother is very tall, interesting, ang good at drawning.</em>
<u>Mon frère aîné est très grand, intéressant et bon dessinateur.</u>
<em>OR</em>
Mon frère aîné est très grand, intéressant et est doué pour le dessin.
<em>My dad is good at work</em>
Mon père est bon au travail = mot à mot, but not really correct in French
<u>Mon père est doué dans son travail.</u>= much better
there's no direct translation for "good at" ==>
est bon à..
est doué pour
est doué dans..
it depends what you're talking about
good at drawning = is a good illustrator, cartoonist .. there's no translation for dessinateur as a general word
est un bon dessinateur = is good at drawning
est doué pour le dessin = is good at drawning
good at his work = depends which work he is doing
hope this helps ☺