I'm so sorry you lost your sister and I agree with Leed. It's his loss.
Keep yourself busy and make small goals for yourself. If you are calling him daily or more you're just boosting his ego and destroying what's left of your confidence. First goal..tell yourself. I'm not calling him today. I'll call tomorrow. When tomorrow comes. I'm not calling today. I'll try tomorrow. Also, if possible. Change your phone number/keep it blocked so you wont know he hasn't tried to contact you. Its helped me with my separation.
time will heal this too.