giving up house with reverse mortgage but needs furnace

[Joe Smith]

so i am wondering

my grandmother has a reverse mortgage she is going to be giving the house back to the bank in two or three months. it has the original furnace from the 1960's in it and it died so she needs a furnace but she can not afford the furnace

she owes way more then the house is worth

if i buy a new furnace and have it installed will i be able to take it back when she give the house to the bank?

i would hate to see her have no heat or hot water for the next two or three months but i definitely don't want to spend $3,000 to $5,000 on a furnace for her just to give it to the bank in a couple months

what are my options for this situation?

thank you for your time