Buying Mother's House while Saving for a Mortgage

Me (32m) and my partner (29m) are currently saving for a mortgage in Dublin. We have about 30k saved for a deposit so far. Hoping to raise it to 40k in the next year. Looking for a small house/ apartment.

My father died in May and my mother decided she doesn't want to deal with the upkeep of their house in Kerry. She is contemplating selling her house (roughly for 130k) and moving into a modular home in my sister's back garden.

My sister has suggested that I use my deposit to buy my mom's house so I can have it as an investment and make money from rental income etc. As it is souch cheaper than Dublin etc.

Is this a good investment/idea while I am saving to buy my own house? Short term I would have to use my deposit but would it work out better long term? We have no plans to move back to Kerry.

I am really clueless. Any help appreciated.