If the game is anything like MPQ (Marvel Puzzle Quest) and the drop rates for top tier characters/cards are abysmal then the amount of money he is spending is a lot more than $10,000.
(Warning, extreme nerdiness follows to try and explain just how much shithead phil spends)
All these mobile games obviously have in game currency that can be used to summon for new characters. You use real money to buy the currency. The going rate for a multi summon in MPQ is $20 (3,000 hero points). The chances of pulling a top tier (5*) character is actually 0 in those types of summons. Only super special currency (command points, 25 for 1 pull) or token can be used to have a slim chance at a 5* character. Now, if you buy a big enough package, 20,000 hero points for $100 you’ll get 7 command points.
Still with me?
So if you spend around $350 you’ll be able to afford 1 pull for a possible 5*. Keep in mind it takes 13 pulls of the same character to max out any character. And those have to be lucky pulls because each character has 3 skills. Each skill can have a max of 5 cards in it. So a character can be 5/5/3 and that is max. However, if you keep pulling a card that you already have a 5 in, it’s useless (unless it is maxed and than championed which means the extra cards can go into breaking the level cap of that character)
All the while these pulls can yield no 5* for 20-30 pulls. The rates are extremely low to the point of futility. 5% I think per pull.
On average a top whale will spend $300-500 weekly in these games for summons and shields for pvp events.
Here is a random top whale in MPQ in an event currently going on.
9 maxed out 5* with a few others nearly maxed.
For more reference as to how much these games can cost a single player:
The rabbit holes are deep in these games. Go watch any DBZ Dokkan Battle summon video (for new events and chars) and watch losers drop hundreds to thousands of dollars on a single event to try and summon 1 character.
The games are fun and addicting but they can also be played for free on high levels if you know what you are doing.
While I have no knowledge of the WWE mobile game I do have extensive knowledge on other similar games like MPQ (been playing since launch, 2,107 days currently, money spent on the game was probably about $200 in the beginning for PvP shields, and my highest 5* character is 2/0/3, now I sign in daily for dailies and rarely do events) and Dokkan Battle (only spent $20 on this game and I have a pretty strong and capable roster). So I can answer questions to a degree if anyone has them.