It does sound as if you are in a lodging as the Son being a blood relative will be your landlord. It may be though that your agreement that was drawn up will give you more rights rather than less. As a lodger you do not have security of tenure. However the landlord should give you notice which matches your frequency of rent payment. i.e. if you pay monthly he should give a months notice or if weekly a weeks notice etc. This would be for any change to your agreement or if giving you notice to leave.
Ultimately it is your choice if you want to stay, as asked earlier -how will the new rent compare to the market, will you be able to find something similar for the rent you are currently paying? If not then it is a simple decision on whether you want to continue living there or not. I should add that the landlords notice period requirements also apply to you so you can give a months notice or a weeks notice etc.
