Advice please?

Im quite new to reddit so hoping its okay to post this here. Also, sorry for any formatting, I'm using my phone to type this. I'll give a general outline first: Recently I've been spending a lot of time with two daughters of an old family friend, they are 7 and 10. Their mum died in January after a fight with cancer and she was the main care giver. Since then, their dad, Pete has been doing what he can but has struggled as he only really disciplined the girls previously due to being out at work and having other commitments.For a while I've been helping the girls with their homework each night after collecting them from school, occasionally cooking their tea and supper if Pete has had to work late, attending reward assemblies, and taking the older of two to open evenings for secondary schools. I also baby sit on weekends over night. They have gotten very attached to me.I had a preplanned holiday to spend some time with my long distance partner, and I was hoping a little space from me, for two or so weeks would help them maybe lose some of the attachment. I've stayed in contact with Pete, and he's said the girls are moping and playing him up a bit, while asking when I'm coming home. I have never planned to stay in my home town, but moved back in with family to have an op which I'm still recovering from. Im only 20 my self. I have said to Pete however, when and if I move away the girls would be welcome to spend some weekends or holidays with me.I'm hoping for advice on how to best handle their clingy behaviour, and how I can help them best to improve. Im already helping them with their homework and further their reading skills, and I want to take them swimming so I can teach them how to swim. What else can I do to help them develop themselves? How do I have the period talk with the older of the two? Ive already explained a bit but my periods are far from normal so I dont know how best to explain to her about what to expect.Again sorry about formatting or grammar/spelling. It may show up as editted as I accidentally posted early. If I can give more information that may help you give better advice then please let me know. I want to do the best I can for these girls. Thank you. via /r/Parenting http://ift.tt/2cM5tcY