sec 22 rightly applies in yuor case. Have to obtain order from court. IN same partition suit, amend the prayer with injunction/cancellation of sale and preemption to purchase the sold portion of land.

Preemptive right direction will issue by city civil court.

Yes you have a preferential right under easement law to buy the same from other legal heirs. But the price quoted should be at par

In partition suit filed your father must have sought injunction restraining co parcener from selling the property 

2) amend the plaint seek orders to set aside sale deed executed by cousin or file separate suit in same  court 

1. File in the district level Civil Court, having jurisdiction over the land area Taluka.

2. If you are personally not able to attend court, THEN a registered POA can be given for the specific purposes (court case & execution) to a close confederate /relative /friend.

3. CONSIDER THIS:  IF land was "ancestral" THEN such land CANNOT be Sold to an outsider person, without proper demarcation and a registered partition deed.  However, under a Family Settlement, an family person can buy such land without partition etc....

Hi

First of all file a interim injunction application for having a stya over the sale of that land.

Then file for the preferential rights in the civil court. 

Thanks

Pre-emption:

Section 22 of the Act is as under:-
“22. Preferential right to acquire property in
certain cases – (1) Where, after the commencement
of this Act, an interest in any immovable property of
an intestate, or in any business carried on by him or
her, whether solely or in conjunction with others,

devolves upon two or more heirs specified in class I
of the Schedule, and any one of such heirs proposes to
transfer his or her interest in the property or business,
the other heirs shall have a preferential right to
acquire the interest proposed to be transferred.
(2) The consideration for which any interest in the
property of the deceased may be transferred under this
section shall, in the absence of any agreement
between the parties, be determined by the court on
application being made to it in this behalf, and if any
person proposing to acquire the interest is not willing
to acquire it for the consideration so determined, such
person shall be liable to pay all costs of or incident to
the application.
(3) If there are two or more heirs specified in
class I of the Schedule proposing to acquire any
interest under this section, that heir who offers the
highest consideration for the transfer shall be
preferred.
Explanation.- In this section, “court” means the
court within the limits of whose jurisdiction the
immovable property is situate or the business is
carried on, and includes any other court which the
State Government may, by notification in the Official
Gazette, specify in this behalf.”.

In a judgment in a civil appeal in supreme court in the case 

CIVIL APPEAL NO. 2553 OF 2019

(Arising out of Special Leave Petition (Civil) No.31039 of 2018)

Babu Ram ...Appellant

VERSUS

Santokh Singh (deceased)
through his LRs and others ...Respondents;  

it was held that 

the bench explained, how right of pre-emption would work

• Three persons, unrelated to each other, had jointly purchased an agricultural holding, whereafter one of them wished to dispose of his interest. The normal principle of pre-emption may apply in the matter and any of the other joint holders could pre-empt the sale in accordance with rights conferred in that behalf by appropriate State legislation.

• If those three persons were real brothers or sisters and had jointly purchased an agricultural holding, investing their own funds, again like the above scenario, the right of pre-emption will have to be purely in accordance with the relevant provisions of the State legislation.

• But, if, the very same three persons in illustration (b) had inherited an agricultural holding and one of them was desirous of disposing of his or her interest in the holding, the principles of Section 22 of the Act would step in.

As per the contention in your query it appears that you are not a shareholder nor a joint holder in the property being partitioned among your father and his siblings, hence in my opinion, this  law may not entitle you to claim preferential rights under this situation.

When there is division of property between
heirs provision is made in the deed that in case of
any one selling his property first preference is given
to the other heir to purchase thep is called
the right of pre-emption. If after giving him notice if
he does not agree to purchase the property he
can sell to other.If the seller does not abide by the
rule,other heir can file suit to establish his right of
preemption and sue for cancellation of deed.

1. In this case your father should make application for amendment of plaint in which another issue for set aside the sales deed should also be included along with application for stay on futher transfer of property.

2. Or you can file another suit for preferential right in civil court to claim your right over the land.

When the partition suit is pending how can he sell the land. The sale is illegal and the person who buys it knowing that it has been sold and is an ancestral property would be in loss too.