More info would be helpful - tank size, what is in it, temp, when set up, etc.
I presume you are doing a fishy cycling? When (& how much) was your last water change? How much are you feeding the fish? Did any routine changed?
What test kit are you using?
It is always dicey to leave things to a fish-sitter during cycling .... unless the person is experienced.
Based on the limited info, I would think:
1. You are past the first part of the cycle. (You did have an ammonia spike before it became undetectable, right?)
2. The 0.25 of ammonia may be a test error .... You might be reading the chloramines in the tap if you just did a recent water change.
3. The nitrites coming down *may* be a sign that the cycle is finishing, but you can't tell until you get a bit of a trend. You might not be seeing much nitrates just yet ... considering that most kit can't read anything below 5, and you have only 0.5 or so of nitrites. <Which will only convert to 0.5 of nitrate ... so it takes a few days to see a level.>
Unless your sitter can reliable monitor levels & do pwc as needed, the best thing for your sitter to do is:
1. Feed VERY sparingly (maybe every other day) to decrease the amount of waste.
2. Watch daily for signs of nitrite/ ammonia poisoning ... rapid breathing, etc. Do water change at any sign of trouble. <Depending how much you trust the sitter to do water change, you can either have him/her do a small water change daily just in case (say 10% - less chance of major tank problem with small pwc), or do pwc only in emergency.>
You should do a large (maybe 50%) pwc (matching water parameters & temp of course) just before you leave, giving the tank a bit of room to deteriorate just in case.