ask him. if he needs a break see if there is anything that you can do to help him out. is he married? single? have any other children? you know him and you know the responsibilities that he has, maybe he needs a break from them.
one thing i strongly warn you against is if he is single, and you 2 have a romantic thing going on (i dont know, you dont tell me if hes married/dating or if you are married/dating) dont let this become a time that he looks to you for emotional connection. be there for him, and all of the things that entails. but dont let this get romantic right now. hes really hurting, and this isnt the time to complicate that.
but, you dont say that it is a possibility, so i should get off that topic.. :P
otherwise, maybe he needs help picking up groceries. maybe he needs you to just pray for him. maybe he needs greif counseling? its really hard for me to tell you what you need to do because of the lack of details of the situation. but you know him and you likely know the things he has to do in his life, and if you can help him in any way, you would know what that is.
HOWEVER, if you are married or in a relationship, your family comes first. do not do things for this man at the expense of your family. :)