Hi Nischal. My Dad was deaf/hard of hearing. He came up with a good solution. There are bed shaking devices available for sale on Amazon (and elsewhere) that will connect to your phone via bluetooth. The device goes under your pillow (or shoulders, whatever you prefer). Then if your phone rings, your bed will shake. It worked well for my Dad. I cannot recommend a specific unit but do an Amazon or Google/Shopping search. You will see several. Just be sure they work with your iPhone.
On a side note, there are also bluetooth devices that will start flashing bright lights when the phone rings. That was not enough to wake my Dad but he had one of these units set up in his TV room. There, he noticed the flashing.