I’d say that biggest factor which blocks this is cluttered emotions and thinking. These things block spiritual abilities more than anything else. My psychic vibe is you have a lot of desperation and anxiety connected to this person and this isn’t helping in your ability.
Once you get that cleared up, when you try to connect with someone you will tend to get better results. Telepathy isn’t so much about learning some new skill as it is about getting rid of what’s blocking it from normally happening. There are some advanced techniques which will help to connect with someone, although the most important thing is to have a clear channel.
This person may be too cluttered to sense your communication, but you will be able to at least send the signal and pick up what this person is going through.