The most important thing to keep in mind about a sublet situation is that the subletting tenant has absolutely no responsibilities to you. If the rent is not paid, you must go after the original tenant. If there is damage to the property, you can only go after the original tenant to recover payment beyond the security deposit. However, if a situation turns bad and gets to the point of eviction, you can evict the person who is subletting the property – but, at the same time, you must evict the original tenant. On the same note, since your original tenant is now acting as a landlord to the person who is subletting, your original tenant can have the subtenant evicted all by themselves.
Since the subletting tenant does not answer to you, and has no agreement with you, rent payments should come directly from your original tenant. Yes, you can take them directly from the subtenant, there is no law against it, but you want to be sure to maintain legal boundaries – so there is no confusion later on if something goes wrong. But, just as the subletting tenant doesn’t answer to you, you don’t really answer to them either. If for some reason you violate the terms of the original lease, only the original tenant can sue you. Of course, if you do not provide a basic, habitable property, your subtenant can most likely seek intervention from the courts.