Hi, I'd like to help you with your question.
It sounds like he is not as invested in the relationship as you are. Part of that is understandable with a sick mother. You need to look at how much care his mother needs and compare it with how much attention he is giving you. Is his mother so sick he cannot leave her alone? If she needs 24 hour care, he may be obligated to be there a majority of the time. In that case, he could be exhausted and not have the energy for a relationship right now. If that is the situation, you may want to back off for a time until he can work out other arrangements. Or if his mother is ok with it, you could see him more often at his home. It depends on how his mother feels about having others in the home while she is ill.
If his mother just needs someone around once in a while and either he has help or just doesn't need to be there that often and is choosing to do other things, then he is not invested in your relationship and you may want to reconsider being with him.
Also, were the reasons you broke up the first time ever been addressed? If this is repeat of how your relationship went before, then you may want to back off. You need time to figure out if the problems between you can be resolved and your relationship can work.
Let me know if I can help any further,