Should he obey his parents and marry someone who is not religiously committed?

Firstly: 

The Prophet’s advice to anyone who wants to get married is to choose a woman who is religiously committed, who will help him with regard to his affairs in this world and in the Hereafter. The Prophet (blessings and peace of Allah be upon him) said, encouraging marriage to one who is religiously committed: “Women may be married for four things: their wealth, their lineage, their beauty and their religious commitment. Choose the one who is religiously-committed, may your hands be rubbed with dust (i.e., may you prosper).” Narrated by al-Bukhaari, 5090; Muslim, 1466.  

We have previously discussed the description of the religiously committed woman whom the Prophet (blessings and peace of Allah be upon him) encouraged a man to marry, in the answer to question no. 96584 

Secondly: 

We do not think there is any conflict between what you want and what your parents want from you. Your parents have stipulated a condition that is well founded in many cases and in many environments. What we think is that you should respond to their wishes and look for a suitable wife outside the family circle, but at the same time you should look for one who is also religiously committed, outside the family circle. Thus you will be able to fulfil both interests and combine the two wishes. This will make it easier for you and will spare you from confronting the family with something they do not want, and you can convince your parents that it is right and to accept your choice. This will be easy, in sha Allah, when you give them what they asked of you. 

Thirdly: 

If it is possible for you to sit with the fiancée or the one to whom you want to propose marriage, in the presence of her mahram and without being alone with her, and adhering to proper hijab, then in that case there is nothing wrong with talking together to the extent that is necessary and in such a way that does not cause fitnah or provocation of desire. You can tell her what you expect of her in the future, and she could tell you what she expects of you. 

But we do not think that you should go to extremes with regard to these questions, or to base your judgement on this meeting; rather what you should do is ask about the girl, not ask her. Before you enter the house you have to find out about the house and its people, and the girl and her situation. And there is nothing wrong with you seeking the help of your sisters and female relatives in this matter. Once you find the qualities you are looking for, then go ahead with the marriage. 

With regard to the questions that you may ask, they will not necessarily yield the answers you are looking for. 

With regard to your financial and social situation, what you have to do is tell the truth about that, because it will have an impact on many things in your married life later on and the rights that your wife has over you. It is not acceptable to enter a house and look at its womenfolk, then when they accept you, you say: I cannot afford any mahr (dowry)! 

Fourthly: 

It is not permissible for you to disclose your previous sins to the one whom you want to marry. So long as Allah, may He be glorified and exalted, has concealed you (your sins), then you have to cover yourself. The Prophet (blessings and peace of Allah be upon him) said: “Avoid this filth that Allah has forbidden. Whoever does any such thing, then let him conceal it with the concealment of Allah.”

Narrated by al-Bayhaqi; classed as saheeh by al-Albaani in as-Silsilah as-Saheehah, no. 663 

It was narrated that Abu Hurayrah said: I heard the Messenger of Allaah (blessings and peace of Allah be upon him) say: “All of my ummah will be fine except those who commit sin openly, and it is part of committing sin openly for a man to do something at night, then in the morning when his Lord has concealed him he says: O So and so, I did such and such last night, when his Lord had concealed him all night, but in the morning he discloses that which Allaah had concealed for him.” Narrated by al-Bukhaari, 5721; Muslim, 2990. 

Fifthly: 

The believer is enjoined to fear Allah, may He be glorified and exalted, in secret and openly. This fear that is required in Islam is the fear that motivates one to do more good actions and righteous deeds, and to keep away from disobedience to Him. But if this fear leads to despair and hopelessness and failing to do good deeds, then it is a kind of devilish whisper (waswaas) by means of which the Shaytaan seeks to divert the hearts of the righteous from the straight path, then he makes them grieve because of that. Allah, may He be exalted, says (interpretation of the meaning): “Secret counsels (conspiracies) are only from Shaitan (Satan), in order that he may cause grief to the believers. But he cannot harm them in the least, except as Allah permits, and in Allah let the believers put their trust” [al-Mujaadilah 58:10]. 

So seek the help of Allah and put your trust in Him; spite the Shaytaan by obeying Allah, may He be glorified and exalted, and humiliate him by strengthening your connection to your Lord. Seek the help of Allah and do not feel helpless. 

And Allah knows best.