Original text: I’ve read an article (1) about that Trump (2) used to obtain huge money from his father and (3) about that that by (4) passing this money to his children via dummy (5) short-live (one day-live) companies Fred Trump (6) was walking away from taxes on tens of million (7) dollars.
(1) It sounds odd to use "about that" together. "about" describes a subject being discussed; "that" is a relative pronoun to introduces more information about a noun. If you wish to use "about" only, you can write: "I’ve read an article about Trump, claiming ...". On the other hand, if you wish use "that" only, you can write: I've read an article claiming that Trump...". (The article is making a claim about Trump, and you can use "claiming" to express this meaning).
(2) When one acquires wealth or possessions from a family member or relatives upon their demise, we can use "inherit".
(3) You do not need "about that that" because you already have the coordinating conjunction "and", so whatever comes after "and" is also a claim made by the article.
(4) You can use "transfer" to describe the movement of assets or money.
(5) You are using an participial adjective to describe Trump's companies. A participial adjective is derived from participles that commonly end with -ed, -ing or -en (i.e. short-lived).
(6) Your main emphasis here is on something done in the past (past simple tense), not so much of a process.
(7) You need a preposition "of" to show that "tens of millions" is referring to "dollars". Example: Tens of thousands OF spectators packed the stadium.
Putting all these together, the edited sentence is: I’ve read an article claiming that Trump inherited massive wealth from his father, Fred Trump. By transferring his money to his children via dummy, short-lived companies, Fred Trump walked away from taxes which amounted to tens of million of dollars.
There are many ways of editing, and mine is just one of them. I hope this helps.