Sam Black 442

bit of a mad one.... ....what I require is that when the communal intercom is called from downstairs at the main entrance to a block of flats, the intercom rings in the flat, my father who has parkinsons needs a solution to be able to answer the intercom and release the door without rushing and falling over. Heres the problem, when the intercom rings he struggles to get to the door in time if its somebody who isn't aware of his condition. I need a solution to have some type of set up whereby, when the intercom is activated that another device can pick up the signal and via WiFi he can be able to make the person aware that he is in and release the main door downstairs. He can then be assured that the delivery driver etc is aware he is in and he can take his time answering the flat door and not falling over. Any suggestions will be hugely appropriated. Thanks Sam