Wa `alaykum assalam wa rahmatu Allah.

Maintaining a good relation with blood relatives is obligatory in Islam. It is prohibited to dissever relations with your relatives. The Qur’an reads: “So would you perhaps, if you turned away, cause corruption on earth and sever your [ties of] relationship? Those [who do so] are the ones that Allah has cursed, so He deafened them and blinded their vision.” (Muhammad 47:22-23)

It is not necessary that your relatives maintain their relations with you and your families in order to do good for them. `Abdullah ibn `Amr ibn Al-`As (May Allah be pleased with them) reported that the Prophet (peace be upon him) said, “The person who perfectly maintains the ties of kinship is not the one who does it because he gets recompensed by his relatives (for being kind and good to them), but the one who truly maintains the bonds of kinship is the one who persists in doing so even though the latter has severed the ties of kinship with him”. (Al-Bukhari)

Abu Hurairah reported that the Messenger of Allah (peace be upon him) said, “Ties of kinship (rahim) are derived from the All-Merciful (ar-Rahman). They say: ‘My Lord! I have been wronged! My Lord! I have been cut off! My Lord! I have! I have!’ Allah answers them, ‘Are you not content that I cut off the one who cuts you off and I maintain connections with the one who maintains connections with you?'” (Al-Bukhari and Muslim)

Therefore, you do not have to make istikharah for things which are clearly prohibited. You have to maintain your good relations with them even if without exchanging visits.

As for making istikharah, it is recommended to make it in almost all of your affairs even if they seem unworthy. Jabir (may Allah be pleased with him) reported that the Messenger of Allah (peace be upon him) used to teach us the istikharah (seeking guidance from Allah) in all matters as he would teach us a Surah of the Qur’an. He used to say: “When one of you contemplates entering upon an enterprise, let him perform two rak`ahs of optional prayer other than fard (obligatory) prayers and then supplicate: “Allahumma inni astakhiruka bi `ilmika, wa astaqdiruka bi qudratika, wa as-‘aluka min fadlikal-`azhim. Fainnaka taqdiru wa la aqdiru, wa ta`lamu wa la a`lamu, wa Anta `allamul- ghuyub. Allahumma in kunta ta`lamu anna hadhal-‘amra (and name what you want to do) khairun li fi dini wa ma`ashi wa `aqibati amri, (or he said) `ajili amri ajilihi, faqdurhu li wa yassirhu li, thumma barik li fihi. Wa in kunta ta`lamu anna hadhal ‘amra (and name what you want to do) sharrun li fi dini wa ma`ashi wa `aqibati amri, (or he said) wa `ajili amri wa ajilihi, fasrifhu `anni, wasrifni `anhu, waqdur liyal- khaira haithu kana, thumma ardini bihi.” (O Allah, I consult You through Your Knowledge, and I seek strength through Your Power, and ask of Your Great Bounty; for You are Capable whereas I am not and, You know and I do not, and You are the Knower of hidden things. O Allah, if You know that this matter (and name it) is good for me in respect of my deen, my livelihood and the consequences of my affairs, (or he said), the sooner or the later of my affairs then ordain it for me, make it easy for me, and bless it for me. But if You know this matter (and name it) to be bad for my deen, my livelihood or the consequences of my affairs, (or he said) the sooner or the later of my affairs then turn it away from me, and turn me away from it, and grant me power to do good whatever it may be, and cause me to be contented with it). And let the supplicant specify the object.” (Al-Bukhari)