Gifting property from mother to son

Hi Sir/Madam, I have purchased 2 bhk flat in 2013-14 when my salary was not that much enough to get the home loan sanctioned I expected. As my wife was jobless, so I took my mother as applicant who was working in school as a teacher and I was the co applicant in my property. This is not my father's /ancestral property. From day 1 onwards, I am paying all EMIs from my bank account, each and every transaction is made through my account. 1. Light bill, gas connection in my name 2. Sale deed, apartment declaration, agreement, 7/12 extract all with joint name. At this stage, we have good bonding amongst our 3 brothers, but to avoid certain clashes in future I have few questions as follows. My questions are : 1. Which type of deed should I execute to transfer it to my name solely so as to avoid further disputes in court of law ? 2. Shall I ask mother to sell flat to me to make me as a sole owner ? (by paying all heavy charges) 3. Can it be challenged in future by my brothers if I made gift deed now ? Please provide your suggestion.