Dear @Anit ji, although Vaastu Shastra advise to avoid to keep photographs of deceased people and pay homage on regular basis, in my opinion, this case does not seems like one. As a Teacher yourself, you may observe that the misfortune this family is facing is for long and the elder soul departed might be one another victim of this misfortune. His photograph in a shelf feel unlikely to affect negatively (it may be put off if such feeling arises).
But yes, the Vaastu of the the House has much to do with it. You may suggest to check on the same thoroughly and my feeling is that a major distortion could be found there. In this connection, we are eagerly waiting for Sharat Sir’s latest blessing (invention) to be launched very soon. After super duper success of VK, this tool may revolutionize the arena of energy once again.