As of now first stop to helping you brother, only take the responsibilities of your mother. And take the help of your middle brother and mother to sell the property which your father has purchased and you have built.

Try to arrange a marriage function between your mother, middle brother, and you in the Mumbai area or outside your village. Do not involve you elder brother and his wife to arrange your and your middle brother marriage.

Get the first family meeting between you and all siblings and mother for partition of property and whatsoever expenses you have made it till date.

If your elder brother did not listen to you, then you can go with a court partition of the property.

Sell the house and distribute sale proceeds among mother and siblings 

if it is not possible file suit for partition for division of house by metes and bounds 

Act as mentioned herein above 

If you have evidence for construction of building and shops, you can issue a legal notice to them to vacate them or to return your money.

Until then you start collecting the rent.

If they oppose then you can approach court with a suit to declare that they belong to you or direct them to return your money.

The building belongs to your father hence you have a right in it, so you can file a suit for partition also.

If it is indivisible then the court may bring the property to sale and distribute the sale proceeds to all the legal heirs.

All the children including your mother will be entitled for a share in the property that belonged to your deceased father as a right.

- As per law , after the demise of your father intestate, his property would be devolved upon all his legal heirs equally. It means that out of 3 bothers and 2 sisters and mother, you have 1/6th share in the property left by your father. 

- Further, as you have constructed the shops in that property , then either you can claim the expenditure of the same or can claim ownership of those shops legally after fling a declaration suit before the court after submitting the fund proofs. 

- You can send a legal notice for the same , and if refused then file the said suit before the Court. 

As construction is made on land purchased by father, land with structure becomes ancestral property. File a suit for partition  of property detailing expenses incurred by on construction, medical and other expenses. As construction is not divisible, it has to be sold through court auction and proceeds divided as per share of each sharer. Offer to purchase house at auction, adjust the  expenses incurred by you in construction and other under other heads against sale price. This is established procedure  under law.

Dear Client,

In the Present case, your father had bought a land, solely on his name, and passed away, leaving behind three brothers and two sisters, out of which, you, the youngest, and your middle brother are unmarried, and your elder brother and two sisters are married. You have also invested around Rs. 15 Lakhs for building three shops and a floor, paid off your father's loans, covered major medical expenses of your mother and father, and additionally, your elder and middle brother have also borrowed Rs. 2 Lakhs, and 1 Lakh from you for business, covering a total of around Rs. 40 Lakhs. Presently, your elder brother and his wife are causing conflicts making it difficult for you to visit home, and are hindering marriage discussion, which you feel could be a way to get the whole property. Under the Hindu Succession Act, 1956, after your father's death, all his legal heirs, including you would be entitled to a share in the Property, and it is not possible for your elder brother and his family disentitle you of the same. Furthermore, for the loans your brother has borrowed from you, the same may be documented for the purposes of recovering them in future or taking legal action for recovery. You can also seek for Mediation to resolve the disputes, as the same is with regard to family and property. Besides, in case such harassment continues, you may also file a civil suit for causing mental distress to you, or for harassment.

Hope you find this answer beneficial for resolving the dispute.

You collect all the details for the reliefs you are looking for from them,  if possible with substantial documentary evidences,  and then consult a local advocate,  brief him about the history and the remedy you are actually  looking for and instruct him with the details to serve a legal demand notice to them as per law. 

Engage a lawyer for sending legal notice to your siblings 

on father demise all legal heirs are liable for payment of father debts to extent of their inheritance 

you can claim Rs 5 lakhs spent by you for repayment of father debts from your siblings 

- The legal notice should be sent through a lawyer 

- if you have proof of payment of loan of your father , then you can claim equal share from other legal heirs