There could be several reasons why an ex-boyfriend would text his sister to ask about his girlfriend when she has blocked him from contacting her directly:
Desire for information: The ex-boyfriend might still have feelings for his girlfriend or be curious about her well-being and current situation. He may hope that his sister can provide updates or insights into how his ex-girlfriend is doing.
Seeking reconciliation: The ex-boyfriend might be interested in getting back together with his girlfriend and believes that reaching out to his sister could be a way to indirectly communicate his intentions or show that he still cares.
Lack of closure: If the breakup was abrupt or emotionally charged, the ex-boyfriend might be struggling to move on and is seeking closure or understanding about the reasons behind the breakup.
Third-party mediator: The sister could act as an intermediary between the ex-boyfriend and his girlfriend, especially if there are unresolved issues or misunderstandings between them.
Respect for boundaries: While he may have been blocked, the ex-boyfriend might be trying to respect his girlfriend's decision to create space by not directly contacting her. Instead, he may think it's more appropriate to approach her through a mutual acquaintance like his sister.
Genuinely concerned: The ex-boyfriend might be worried about his ex-girlfriend's well-being or safety and feels that contacting his sister is the only way he can express those concerns.
Emotional support: The ex-boyfriend might have a close relationship with his sister and feels comfortable sharing his feelings and seeking advice or comfort during this difficult time.
It's important to note that every situation is unique, and the actual reasons can vary depending on the individuals involved and the specific circumstances surrounding the breakup. However, it's essential for both parties to communicate openly and honestly to resolve any lingering issues or misunderstandings constructively. If the ex-girlfriend is uncomfortable with this indirect approach, she should communicate her boundaries clearly to her sister and the ex-boyfriend.