It used to be the case that a Christian
burial was denied to a person who
had committed suicide because it
was considered an act of final despair.
Because of that horror, and
the desire to teach Christians that
final despair was damning, the Church
refused a Christian burial.
We now know that suicide is often
a sign of mental illness [and|or]
a lack of full awareness and consent
is involved, so the Church does grant
a Christian burial.
If you talk to your local Catholic
cemetery, you will get information,
or you can speak to the pastor of
the parish in which the person lived.