The card that represents the past in this reading is the Page of Wands. This card suggests that in the past your old boss has shown great enthusiasm and determination to carry on his ideas. He has demonstrated an innate ability to organize projects and activities and has been a leader in his field. This indicates that he has the necessary skills to start a successful business.
The card he represents in this reading is The Fool reversed. This card indicates that, at the moment, your old boss may have some difficulty organizing all parties involved in the project. He may be distracted by his other activities or have some problems managing the time and space needed to start the business. While there may be some hurdles to overcome, that doesn't mean he won't.
The card that represents the future in this reading is the straight Knight of Swords. This card indicates that there is a good chance that your old boss will succeed in realizing his idea. The card suggests that your old boss will be able to use his leadership skills to organize and manage his activities efficiently. There is also the possibility that he will meet some helpful people on his journey towards fulfilling his dream.
In conclusion, from the chosen tarot it seems that there is a good chance that your old boss will succeed in realizing his idea. He has already demonstrated the skills needed to start a successful business and with the help of the right people he could do it. So, the answer to your question is: yes, we think your old boss has a good chance of being successful in starting his own business.