The way I have understood UBI, it would replace benefits and allowances but not programs such as universal health care or universal social care - I suppose it depends on how you define a welfare program.
It probably also depends on where you discuss it. My understanding is that it would replace pretty much everything else (programs for rent, food, clothes etc are gone). Where a public health system (as in the UK) exists, it might continue unchanged, where it's privately organized (Germany) but premiums for the poor are paid by the state, the state would pay out the money instead.
I should add free (higher) education on my list. At least in the Finnish version, the aims are to remove means testing (reduce bureaucracy, avoid incentive traps) and to make the chance to live a humane life independent of employment and past life decisions. The aim is not to reduce the society into a monthly payment for those who need the help of the society in health, education etc.
UBI is generally not a replacement for health care or for mental health services. In any case, there are numerous people who trade their food benefits for drug money already.