Could you daven for someone who got sick with CoronaVirus, if he was not wearing a mask?

A talmid chochom asked Rav Yitzchak Zilbershtein, Rav of Ramat Elchonon neighborhood of Bnei Braq, if he should daven for someone with CoronaVirus, after the fellow had refused to heed warnings and wear a mask. The story goes that in this shul they say tehillim for people with CoronaVirus, led by this talmid chochom (I will assume it is the rav of the shul, even though the article in Kikar does not say so), and then people submit names of the sick people for the prayer for the sick after the tehillim. One person has been going to the shul without a mask. Many people told him to wear a mask, and he continued to refuse to do so. The rav also warned this fellow and when he continued to refuse, the rav warned him that he is actively killing himself and if he gets sick "don't come to me to daven for you".

Sure enough, Mr Brainiac got sick a few days later and even went into critical condition. 

Brainiac's family went to the rav and asked him to daven on behalf of the sick relative, specifically at the various bris mila ceremonies he participates in.

Initially the rav responded saying he won't daven for him - he had warned the fellow and been ignored and he specifically told him not to come back asking for tefillos.

At some point he was not confident his approach was proper, so he asked Rav Zilbershtein if he should be davening for this fellow.

Rav Zilbershtein responded that it really depends. If the fellow was not healthy before he got Corona, then perhaps he was not of clear mind and when he refused to wear a mask it was not a clear conscious decision, so he should be davened for, and if he recovers he should bentch gomel. If, however, he was healthy before he got Corona, then there is no need to daven on his behalf and if he recovers he should not bentch gomel.

My question is the second one asked above. The rav asked if he should daven for this fellow. My question is if he could daven for him. He does not need to, but perhaps he still could. When a person does this to himself, is there no place in us for rachmanus? Does it cost us anything? Does it use up our quota of prayers for other people in heaven and maybe someone else we daven for won't get helped?

I get that there is no need to but could he anyway?