The main practice is to find out what makes her laugh. Encourage comedy and levity so that she works with her belly. The main need is for you two to deepen your relationship and become friends. Obviously she trusts you for some reason or would not consider coming for individual instruction. So build upon that foundation.
Then add pranayama emphasizing gradually moving towards Kapalabhati is recommended. First step before that though is Agnisar dhouti (it is one of the 6 Shatkarma cleansing practices recommended for such people). This is done by doing abdominal breathing as a preliminary then holding the breath after exhales. While holding the breath contract and relax the abdomen as many times as possible. It can be done sitting or standing. The goal is to promote sensitivity to how many is comfortable and where is the red line of feeling stressed. She is encouraged to pause and exercise not hold breath with effort. Gradually her breath pause time is increased and with it digestive fire (agni) is stimulated.
The other practice I would recommend is walking while contracting abdomen on as many exhales as possible then release breath awareness and breath normally for 20-50 steps until recovered then repeat the process. I would wait for a couple weeks to deepen your relationship before attempting my joint freeing series but that would be the first yogasanas I would give her.
