According to the correct scholarly opinion, the repentance of one who has apostatised repeatedly is to be accepted, and he comes under the same rulings as any other Muslim.

To sum up: a dinar is equivalent to 4.25 grams. If the thief is caught, then the qaadi (judge) should look at the price of gold on that day (the day of the theft). If it is proven that the value of the stolen goods on the day of the crime was equal to the value of 1.0625 grams of gold on that day, then the thief deserves the hadd punishment of having his hand cut off. If the value of the stolen goods is less than that, then he deserves a disciplinary punishment (ta‘zeer).  And Allah knows best.

To sum up: what may be stated definitively is that the Sahaabah (may Allah be pleased with them) did not deliberately go against the prohibition on punishment by burning. What has been narrated from some of them (concerning that) is either not saheeh (sound), or it is saheeh but they are excused for what they did on the basis of ijtihaad, because they were qualified to engage therein.  If the mujtahid strives his utmost to issue a correct verdict and fatwa but makes a mistake, he is rewarded and is not regarded as having sinned.  It was narrated from ‘Amr ibn al-‘Aas, that he heard the Messenger of Allah (blessings and peace of Allah be upon him) say: “If a judge passes a judgement having striven to reach a decision, and he gets it right, he will have two rewards. If he passes a judgement having striven to reach a decision and he gets it wrong, he will have one reward.”  Narrated by al-Bukhaari (7352) and Muslim (1716).  For more information, please see Sharh al-Kawkab al-Muneer (4/491-492)  And Allah knows best.