Hello,
1) Regarding money that you gave to your father to clear debts or to deal with legal issues pertaining to property would not be recoverable , in the absence of any document /agreement showing proof of your having lent money to him.
2) Secondly he being the parent is is in a position where he can claim maintenance if he does not have the means to take care of himself.
3) Regarding securing your property: if the property that he is alienating or mortgaging is ancestral you can approach a civil court in India and get a stay order restraining him from alienating or creating third party rights in the property.
4) Of the joint properties your father has 50% right and for the rest of the 50% your father and all of you children are equal share holders.
5) Although you can not demand a partition of the property you can get an injunction restraining your father from further alienating properties further.
6) You can give Power of Attorney to your sister or any one trustworthy in India to act on your behalf and start legal procedures.You could firstly send a legal notice to your father demanding the return of the 20 lacs and warn him of legal action to recover the money and to protect the properties from getting alienated.