Obviously there are more details to this, but in general, I agree with the others above - don't make any rash decision. First, does it really matter if you are in contact with this person regularly? You don't have to cut off the friendship forever just because it's a tough time for you. My wife has had a problem keeping long-term friends and marvels at the number of friends that I have. I explained to her that it's a matter of effort. I had to make a decision as to whether or not each friendship was worth keeping. If the answer to my question is yes, I make the effort to keep the friendship going. That means making calls, sending an Email here or there, remembering birthdays, etc. There are times when a particular friend doesn't respond to messages or Emails and it could easily be interpreted as them not wanting to be a friend anymore.
I've found that sometimes people just have too much going on in their lives to be the person taking care of the relationship at that time. No problem. You just have to be patient. Communicate to your friend by writing a letter or Email and keep sarcasm and finger pointing out of it. Just let them know that you are there for them if they need you and that you understand that they have a lot going on right now. Keep it short and simple and as nice (and supportive) as possible. Then just keep in touch with a phone call or Email here and there over the next whatever amount of weeks and see what happens.
If this is a phase your friend is going through, you may be surprised to find that your friend will eventually appreciate your support at this time and reach out for your friendship. On the other hand, they may not be a good friend after all and you'll lose touch. Either way, you did your best and were a friend to them. Sometimes friendships work out and sometimes they don't. That's just the way it is in life.
Hope that helps a little bit.