Here are few things that your Friend could try:
1) He should try and separate learning from investment: It is quite good for him to accumulate Bitcoin using either the DCA or NCA strategy just like like you advised him to do. However based on his current conditionz I believe that he should spend more of his time( his free times) in learning an actual skill that is maybe crypto related or tech related since he already has an interest in tech. He can stick to platforms that offers free courses like https://www.coursera.org/courses?query=free
https://www.udemy.com/
https://www.mindluster.com/   etc

2). Trimming his spending areas: Even though he is on a tight budget, he should still look for ways to reduce certain leaks in his purse e.g., his food spending could be reduced slightly by maybe changing were he buys his food to a more cheaper restaurant or cooking at home more often. With this act he would be able to realise some amount of money which he can then add to his Bitcoin NCA/DCA.

3). He should join earning communities/ websites: I would have recommended one for him to join but I don't really know communities that pays it's members or participant, but if any of us knows you can help point it out. However I included this point coz I have been told by fiends of mine in past that there are actually communities that pays participants for engaging in one task or the other, they mentioned them but I have actually forgotten.