I know this feeling so very well. In fact I am sitting at my desk, wondering whether to go to a gallery opening that's happening a block away where a former friend is exhibiting. I have lost 90% of my social circle over the last few years mostly due to divorce. I don't know if this will help you but here's a few things I try to remember:
Follow the energy. If some-one wants you in their life and they are genuine, then focus on that person, rather then the one who is not willing to put in the same amount of effort as you.
People can only offer what they can offer. Often what we want, and what some-one can offer, don't match up. If that person is still texting you unprompted then maybe that's all they can offer. The choice is then yours how you want to respond. I would meet them where they are at. Thank them for their contact, continue to contact them in the same manner that they are contacting you. Maintain a connection but don't rely on anything more. One day they may find capacity to increase contact & if that happens, you can decide how far you want to engage.
Protect your energy. Know your worth. Sometimes when people draw together then pull apart again it's because they needed each other to share that moment in time with. You both had history, you both were grieving your mothers. You supported each other through that. Now that the initial grief of your mother's is passing, you don't have that to bond over. Something else may come along. It may not. But if you keep focussed on your worth in the world, rather than just your worth in their world, hopefully you will see others with whom you can bond over this point in your life.
Not sure if any of that helps, but as some-one who knows the extreme pain of the end of a friendship, know that I see you and hope for the best for you.
