Assuming mortgage of home

[Alexander Sierra]

So my grandmother is 80 years old and just stopped working officially last week.She owns a home and stills pays a mortgage on the property and since shes no longer working,does not have the means to pay her mortgage any more.I currently live with her and told her i wouldnt mind paying the full mortgage costs and all the bills that entail in owning a home but i would like to be a co-owner and when she passes the sole owner of the property.The house has been appraised at around 400 thousand and she owes currently about 225 thousand.I wanna know what options i have that maybe i havent heard of or seen,any insight or ideas are greatly appreciated.Thanks in advance,Alex.